187results about How to "Improve solder resistance" patented technology

The invention discloses a lead-free and cadmium-free electrode silver slurry for piezoelectric ceramics. The lead-free and cadmium-free electrode silver slurry for piezoelectric ceramics is prepared from the following raw materials in percentage by weight: 50 to 75 percent of conducting silver micro powder, 0.5 to 5 percent of inorganic additive, 1 to 15 percent of lead-free glass powder and 15 to 45 percent of organic carrier. The lead-free and cadmium-free electrode silver slurry is technologically advantaged in that a boron-bismuth-silicon-zinc-titanium glass system is designed, the traditional lead-containing glass can be completely substituted, a lead-free product is realized, the system glass can react with a piezoelectric ceramic substrate to form a firm interface between an electrode and the substrate, and the adhesion force of the interface is more than 15N / mm<2>.

The invention discloses a high-frequency copper foil substrate with an operating frequency of more than 1GHz, which has a dielectric constant Dk of less than 3.2 and a loss factor Df of less than 0.005 as well as high glass transition temperature, high thermostability and low moisture-absorption characteristic. The high-frequency copper foil substrate contains a special composite material and is prepared by impregnating a reinforcing material with blended resin mixture. The resin mixture of the composite material is prepared by blending the following materials: (a) high molecular weight polybutadiene resin; (b) low molecular weight polybutadiene resin; (c) modified polyphenyl ether thermosetting resin; (d) inorganic powder; (e) flame retardant; (f) cross-linking agent; (g) binding aid; and (h) hardening initiator. In the invention, the drawback of low processability of pure polybutadiene with low viscosity and the drawback of need of adding plasticizer of polyphenyl ether resin (PPE) with low solubility; particularly, the non-viscous pre-impregnated sheets made by the composite material can be processed into copper foil substrates automatically.

The invention provides an adhesive combination. The adhesive combination contains thermoplastic resin, thermosetting resin and a firming agent, wherein the thermosetting resin contains polyphenyl ether with epoxy functional groups at the end, perfluor styrene-methacrylic acid epoxy propyl ester copolymer, bisphenol A epoxy resin and phenolic aldehyde epoxy resin. The invention further provides a flexible circuit board and a covering film which comprises the adhesive combination. The peeling strength of the provided flexible circuit board is from 12 to 16N / cm, the dielectric constant is from 1.4 to 1.8, the dielectric loss is from 0.0013 to 0.0017, the rotating speed is 300 r / m under the working environment (50 DEG C), the flexibility is 180 DEG, the flexible circuit board can be bent more than 12 million number of times, the flame retardance reaches UL to 94V0, and the GTT (glass-transition temperature) of an adhesive is from 200 to 220 DEG C.

The invention discloses an environment-friendly electrode silver slurry of zinc oxide varistor suitable for two soldering technologies and a preparation method of the electrode silver slurry. The silver slurry is composed of 60-80% silver powder, 1-5% of metal oxide, 2-5% of leadless glass powder and 10-37% of organic carriers by weight. The preparation method comprises the steps that the leadless glass powder is prepared by that raw materials are mixed well, placed in a platinum crucible and melt, and the melt material is removed and dried to obtain the leadless glass powder; the organic carriers are prepared by adding an organic solvent into a stainless steel container, adding organic resin, carrying out heating, and carrying out cooling and adding a surfactant after the resin is completely dissolved; and the silver slurry is prepared by mixing the silver powder, the metal oxide, the leadless glass powder and the organic carriers, and stirring and grinding the mixture in a vacuum manner. The preparation method is simple and suitable for both the reflow soldering and immersed soldering technologies, the solderability and the soldering resistance are high, the silver slurry can be used to prepare common type as well as lightning protection type varistor, the adhesion force, the conductivity and the electrical performance are high, and the performance completely reach the using requirements.

The invention discloses sliver electrode slurry for a back electric field of a silicon solar cell and a preparation method thereof, and the silver electrode slurry for the back electric field of the silicon solar cell comprises the following components by weight percent: 60-70% of spherical silver powder, 0-5% of flaky silver powder, 2-6% of glass powder with a high-temperature softening point, 1-3% of glass powder with a low-temperature softening point and 20-30% of organic bonding agent. The particle size of the spherical silver powder is 0.5-2.5 mu m, and the tap density is above 4.5g / ml; the particle size of the flaky silver powder is below 5 mu m, and the tap density is above 4.0g / ml; and the glass powder with the high-temperature softening point is a PbO3-B2O3-SiO2-ZnO glass system, and the glass powder with the low-temperature softening point is a Bi2O3-B2O3-SiO2 glass system. The slurry is applied to a sliver electrode of the back electric field of the silicon solar cell; furthermore, after fast high-temperature sintering by a chained belt furnace, the adhesive capability is strong, the soldering resistance is good and the photoelectric conversion efficiency of a product is high.

The invention discloses a medium temperature sintering type electro-conduction slurry with lead-free glass powder and a preparation method of the medium temperature sintering type electrocondution slurry. The preparation method is characterized by comprising the steps of preparing an organic carrier, preparing the lead-free glass powder, preparing silver powder and preparing the electro-conduction slurry. The electro-conduction slurry comprises, by mass, 0 to 80% of micron-scale spherical silver powder, 5% to 70% of micron-scale flake silver powder, 2% to 25% of the lead-free glass powder and 0 to 25% of the organic carrier. The lead-free glass powder comprises, by mass, 25% to 75% of Bi2O3, 20% to 60% of B2O3, 0 to 20% of ZnO, 0 to 20% of Sb2O3, 0 to 10% of Al2O3 and 0 to 8% of alkali metal oxide. The organic carrier comprises, by mass, 50% to 80% of terpilenol, 10% to 40% ofbutyl carbitol acetic ester, 0 to 10% of tributyl citrate, 3% to 10% of ethocel, 0 to 2% of hydrogenated castor oil and 0 to 3% of addition agent.

The invention discloses a preparation method of nanometer low-silver-content back silver conductor paste for crystalline silicon solar application. The method comprises the following steps of silver powder preparation, organic carrier preparation and nanometer silver conductor paste preparation. In silver powder preparation, a saturated silver nitrate and PVA mixed solution is added dropwise into a sodium borohydride solution, then water bath stirring is conducted, centrifugation, alcohol washing and low-temperature negative-pressure drying are conducted, and then silver powder with the grain size being 1 nm-100 nm can be obtained. According to the preparation method, the self-made nanometer silver powder is used for replacing micro-sized silver powder in existing back silver conductor paste, so that the conductive performance, the printing performance and the crystalline silicon substrate adhesion performance of the paste are changed, and application of the back silver conductor paste in crystalline silicon solar energy is greatly expanded; in addition, according to the method, the adding amount of the silver powder is greatly reduced, existing paste production equipment is used in the preparation process, extra new investment is not needed, environment protection is facilitated, and use of the precious metal silver is reduced.

The invention discloses a surface blackening treatment method for a rolled copper foil. The surface blackening treatment method orderly comprises the following steps: (1) electrochemical oil removal, (2) coarsening treatment, (3) solidification treatment, (4) nickel-cobalt plating treatment, (5) zinc plating treatment, (6) passivation, (7) silicone coupling agent coating treatment, and (8) drying treatment, and obtaining the product. Current is applied in step (1) to step (6). The surface blackening treatment method for a rolled copper foil provided by the present invention has the advantage that the black appearance of the copper foil obtained after various electric plating steps meets FPC requirements. Through determination, the copper foil has a surface color blackness value of less than 30, surface roughness Ra of less than or equal to 1.0 micron and Rz of less than or equal to 2.0 microns, peel strength of more than 1.4 N / mm, and folding endurance MIT of more than 800; the copper foil has favorable acid resistance, alkali resistance, soldering resistance, and etching performance. With the blackness value RAL7016, a good extinction effect is achieved.

The invention discloses a conductive paste for the back electrode of a crystalline silicon solar cell and a preparation method thereof. The paste is prepared by mixing and grinding conductive metal powder, a metal adhesive, an organic carrier, and a functional additive in a certain weight ratio. to make. The present invention uses no glass powder as the inorganic binder, which overcomes the poor electrical performance, poor solderability and solderability, and poor solderability and solder resistance of the conductive paste used for the back electrode of silicon solar cells in the prior art due to the addition of glass powder. The back electrode of the crystalline silicon solar cell prepared with this slurry has firm adhesion, good ohmic contact, good solderability and solder resistance, and the solar cell has superior electrical performance and small deformation.

The present invention relates to curable, liquid, adhesive compositions comprising polyamideimide resins for use in bonding layers of material in metal clad laminate materials for electronic components, such as flexible circuit boards. In particular, the invention relates to liquid adhesive compositions comprising polyamideimides having a terminal isocyanate group blocked by a thermally-dissociatable isocyanate-blocking group and the use of such compositions in preparation of flexible electronic components.

The invention discloses solar energy battery electrode-conducting silver slurry containing micron-size mixed silver powders. The silver slurry comprises mixed silver powders, glass powders, organic carriers and mixed silver powders, wherein the mixed silver powders are composed of, by weight, 5% to 15% of silver powders with grain size from 0.1 micrometers to 1 micrometer, 30% to 50% of silver powders with grain size from 1 micrometer to 3 micrometers, and the balance silver powders with grain size from 3 micrometer to 6 micrometers. According to the solar energy battery electrode-conducting silver slurry containing micron-size mixed silver powders, the silver powders are high in tap density and can form dense net with excellent conducting performance after sintering so that the contact area of the silver silicon interface can be increased and the conversion efficiency of battery electrodes is high; the surface of the electrodes is smooth, and the electrodes have good in solderability and strong adhesive force.

The invention discloses liquid photoreceptive solder resist ink, which is mainly formed by combining a main agent and a curing agent according to the mass ratio of 3 / 1. The invention has the beneficial effects that: the double-component screen printing solder resist ink which is printed through double-component screen, is exposed through ultraviolet (UV) light, is developed through diluted alkaline has high resolution ratio; and the coatings after high temperature hardening is carried out have high insulativity, high solder resistance and high watertightness, and can be durable to immersion gold plating and immersion tin.

The invention relates to a poly-amino-bismaleimide resin composite, a preparation method and the applications thereof in copper clad plates. The composite essentially consists of a poly-amino-bismaleimide resin, a phosphorous epoxy, a cyanate resin, a novolac epoxy resin, an inorganic stuffing, a curing catalyst and a solvent. The poly-amino-bismaleimide resin in use is pre-polymerized from bismaleimide and aromatic amine under the reflow temperature with toluene as the solvent. The poly-amino-bismaleimide resin composite used in copper clad plates has good processing properties, low curing temperature (195 DEG C) and short high temperature curing time (1 to 1.5 hours). The prepared copper clad plates have excellent heat resistance, with the vitrification transition temperature ranging from 204 DEG C to 230 DEG C, good fire retardant effect, comparatively high peeling strength, bending strength and comparatively low water absorption ratio.

The invention relates to the field of ink and particularly relates to yellowing-resistant photosensitive solder resist ink and a preparation method thereof. The yellowing-resistant photosensitive solder resist ink is prepared from the following components in parts by mass: 50-150 parts of beta-hydroxyethyl acrylate modified melamine-formaldehyde resin, 40-120 parts of reaction diluent, 5-15 parts of polysilazane resin, 15-50 parts of epoxy resin, 4-12 parts of photoinitiator, 120-200 parts of pigment, 4-10 parts of filler and 4-10 parts of auxiliary. The invention provides yellowing-resistant photosensitive solder resist ink for an LED (Light Emitting Diode); compared with the traditional home-produced photosensitive solder resist ink, the solder resist ink prepared by the invention has the advantages of high reflectance and excellent heat resistance, soldering resistance and yellowing resistance, and is particularly suitable for being used as photosensitive solder resist ink for the LED.

The invention relates to a lead-free glass powder for silver paste on the back of a crystalline silicon solar cell and a preparation method thereof. The lead-free glass powder comprises the following raw materials in parts by weight: 40-70 parts of Bi2O3, 5-15 parts of B2O3, 0.5-5 parts of ZrO2, 10-20 parts of SiO2, 5-20 parts of ZnO, 1-5 parts of TiO2, 5-20 parts of Al2O3 and 1 part of P2O5. The preparation method comprises the following steps of: placing the raw materials in a mixer, and uniformly mixing to form a mixture; preheating a quartz crucible to 600-800 DEG C, placing the mixture in the quartz crucible and carrying out heat preservation for 20 minutes; then smelting for 20 minutes to 40 minutes at 900-1200 DEG C; pouring molten glass into deionized water for quenching, carrying out wet-process ball milling on the quenched glass to 2-5mu m, and drying to obtain the lead-free glass powder. The lead-free glass powder has the advantages that the technological process is simple, time consumption for smelting is short and cost is low; when in use, the lead-free glass powder has good wettability with silver powder and a silicon substrate; and after the lead-free glass powder is sintered, the adhesive force between the lead-free glass powder and the silicon substrate is above 5N.

The invention relates to lead-free electrocondution slurry used for a crystalline silicon solar cell back electrode. The lead-free electrocondution slurry used for the crystalline silicon solar cell back electrode consists of the following components in percentage by weight: 40-70wt% of silver plating copper powder, 2-10wt% of inorganic lead-free glass powder and 25-50wt% of organic carrier, wherein the organic carrier is the mixture of solvent, thickening agent and additive, and the prepared electrocondution slurry printing back electrode has the advantages of big thickness, small bulk resistance, excellent soldering resistance, strong welding adhesive force and silver ion migration resistance. Meanwhile, after cell pieces are subjected to series welding, an assembly has the advantages of higher stability and stronger anti-aging capability.

The invention relates to a resin for semiconductor packaging, and particularly to an epoxy resin composition which can improve soldering resistance of an epoxy resin composition molding material and comprises hydrated alumina (molecular formula AlOOH. The epoxy resin composition comprises the following components according to the following content: 3-14wt% of epoxy resin, 2.5-9wt% of phenolic resin, 0.05-0.5wt% of curing accelerator, 57-89.5wt% of silicon oxide, 0.5-21wt% of hydrated alumina, 0.1-1.5wt% of mold lubricant, and 0.3-1.5wt% of silane coupling agent. The epoxy resin composition with hydrated alumina according to the invention is a semiconductor packaging material with high soldering resistance. Simultaneously the epoxy resin composition has the following advantages: necessary fluidity, necessary moldability, necessary flame resistance and necessary mechanical properties.

The invention relates to the field of manufacturing of LTCC, thin films and mixed base plates, and especially relates to a preparation method for a high-precision resister on LTCC base-plate surface. The preparation method mainly comprises grinding polishing of an LTCC base plate, cleaning, cavity filling, resistor figure making, electrode figure making, annealing and resistor resistance measuring. By employing the technical scheme, the resistance precision of the surface of the LTCC base plate can be improved from original 20%-30% to 5%-10%, the electrode soldering resistance and the film-layer adhesive force are effectively improved, and the line is relatively small, the line precision is relatively high and the application frequency is relatively high.

The invention provides conductive silver paste for a filter and a preparation method and a sintering method thereof, and belongs to the technical field of conductive silver paste. The conductive silver paste for the filter comprises the following components in percentage by mass: 60-90% of silver powder, 1-5% of glass powder, 0-3% of platinum group metal oxide and the balance of an organic carrier, the silver powder comprises main silver powder accounting for 80-98% of the total mass of the silver powder and auxiliary silver powder accounting for 2-20% of the total mass of the silver powder. The main silver powder is spherical silver powder, the auxiliary silver powder is flaky silver powder, the main silver powder and the auxiliary silver powder are high in activity, high in tap density and very concentrated in particle size distribution, and the two kinds of silver powder can complement respective advantages and coordinate with each other after being mixed and matched according to acertain proportion, so that the overall silver paste performance is greatly improved. The conductive silver paste for the filter prepared through mutual cooperation of the components is good in compactness, high in welding resistance, high in Q value, good in adhesive force and high in universality.

The invention discloses a silver paste of a high-performance lead-free crystalline silicon solar battery back electrode. The silver paste comprises, by weight, 30 to 58% of silver powder, 1 to 5% of lead-free glass powder, 0.01 to 10% of graphene, 0 to 1% of inorganic additive, 40 to 68% of an organic adhesive, and 0. 1 to 2% of an auxiliary agent. The mixed silver powder is a mixture including irregularly-shaped silver powder and silver powder with a high specific surface area. In addition, the invention also discloses a preparation method for the silver paste of the high-performance lead-free crystalline silicon solar battery back electrode. Graphene, an auxiliary agent, and a part of organic adhesive are mixed and then the mixture is rolled to form a slurry, so that a graphene slurry is obtained; silver powder, lead-free glass powder, an inorganic additive, and the rest of organic adhesive are mixed and stirred uniformly and then the graphene slurry is added; and stirring and mixing are carried out continuously and uniformly, so that a needed silver paste is obtained. According to the invention, the fusion and contact with an aluminum back field are improved; the contact resistance between the silver electrode and the aluminum back field is reduced; the conversion efficiency of the battery piece is improved; and the electrode weldability and soldering resistance performance are enhanced.

The invention belongs to the field of shielding films, and particularly relates to an electromagnetic shielding film. The electromagnetic shielding film comprises a carrier layer, a first insulation layer, a second insulation layer, a metal layer, a conductive adhesive layer and a protective layer which are in contact sequentially. The first insulation layer comprises polyimide resin. The second insulation layer comprises first resin. The first resin comprises acrylic resin and / or epoxy resin. The electromagnetic shielding film is provided with the first insulation layer comprising polyimide resin and the second insulation layer comprising acrylic resin and / or epoxy resin, it is ensured that high adhesive force is achieved between the insulation layer and the metal layer, and the soldering resistance of the electromagnetic shielding film is remarkably improved. According to the preferential implementing mode, heat conduction materials are added in the insulation layers, and therefore the electromagnetic shielding film has the good cooling effect.

The invention relates to epoxidized soybean oil modified phenolic resin and a method for producing the non-fire-retardant paper based laminate by using the resin, and belongs to the technical field of a production method of a copper clad laminate. The epoxidized soybean oil modified phenolic resin is characterized by comprising the following raw materials in parts by weight: 100-200 parts of phenol, 50-110 parts of epoxidized soybean oil, 0.5-3 parts of amine catalyst, 200-300 parts of formaldehyde, 20-40 parts of nitrogen-containing phenolic resin and 100-400 parts of solvent. The method forproducing the non-fire-retardant paper based copper clad laminate by using the epoxidized soybean oil modified phenolic resin is characterized by comprising the following steps: (1) preparing a resincomposition; (2) preparing a sizing material slice; and (3) preparing the non-fire-retardant paper based copper clad laminate.

The invention provides a glue solution for a copper-clad plate, a composite based CEM-1 copper-clad plate, and preparation methods of the glue solution and the composite based CEM-1 copper-clad plate. The glue solution for the copper-clad plate comprises the raw materials in parts by weight: 1200-2000 parts of epoxy soybean oil modified phenolic resin, 1200-2000 parts of epoxy resin, 150-250 parts of phenolic resin, 300-700 parts of a flame retardant, 250-350 parts of a curing agent, 1-5 parts of a curing accelerant, 50-150 parts of an inorganic filler and 100-300 parts of an organic solvent. On one hand, the epoxy soybean oil modified phenolic resin provided by the invention has the advantages of simple preparation process, good product performance and wide application; on the other hand, the glue solution for the copper-clad plate has the advantages of simple preparation process, good product performance, wide application and good permeability to wood pulp paper; what is noteworthy is that the composite based CEM-1 copper-clad plate provided by the invention has the advantages of simple preparation process, relatively good punching property, relatively good soldering resistance and good processing performance.

The invention discloses a novel pulse metering device in a fuel gas meter end and a metering method, and relates to the technical field of fuel gas metering devices. The novel pulse metering device in the fuel gas meter end mainly comprises a photoelectric sensor, an MCU, a counting gear and a transmission gear. The photoelectric sensor comprises a photoelectric transmitting tube and a photoelectric receiving tube, the photoelectric sensor is used as a metering switch, and the MCU is used for conducting on-off control and signal processing. According to the scheme, reflecting mediums are added to the counting gear and are used as on-off mediums of the photoelectric sensor, when the photoelectric sensor identifies a white medium, the photoelectric sensor outputs a voltage to the MCU, when the photoelectric sensor identifies a black medium, the photoelectric sensor outputs another voltage to the MCU, and then the MCU achieves a metering function by distinguishing signals of different voltages. According to the novel pulse metering device in the fuel gas meter end and the metering method, the novel metering device has the advantages of being accurate in metering, strong in anti-light capability, low in power dissipation and cost, simple in process, high in production efficiency, and strong in anti-interference capability.

The invention relates to an unleaded back silver paste used for a crystalline silicon solar cell and a preparation method of the unleaded back silver paste used for the crystalline silicon solar cell. Raw materials comprise 60 parts of aluminum powder, 29-42 parts of organic binding agents and 1-10 parts of inorganic binding agents, the organic binding agents comprise 40-70 parts of terpilenol, 5-10 parts of butyl carbitol, 5-10 parts of butyl carbitol acetic ester, 3-10 parts of ethyl cellulose, 5-15 parts of diethyl phthalate and 2 parts of sorbitol anhydride stearate, and the inorganic binding agents comprise 30-60 parts of Bi2O3, 5-15 parts of B2O3, 1-2 parts of NaF, 10-20 parts of SiO2, 5-10 parts of ZnO, 1-5 parts of TiO2, 10-20 parts of Al2O3 and 2 parts of P2O5. After being mixed evenly, the components are rolled until the fineness degree is smaller than or equal to 10 microns, and viscosity is 30-100 Pa.s. The unleaded back silver paste used for the crystalline silicon solar cell is high in adhesive force and good in weldability and welding resistance.

One of major objects of the invention is to provide an epoxy resin composition and a semiconductor device exhibiting good soldering resistance when being formed on a non-copper frame. Thus, this invention provides an epoxy resin composition for encapsulating a semiconductor comprising (A) an epoxy resin, (B) a phenolic resin, (C) a hardening accelerator, (D) an inorganic filler and (E) a triazole compound, preferably an epoxy resin composition for encapsulating a semiconductor wherein the triazole compound is a compound represented by general formula (1):wherein R1 represents hydrogen atom, or mercapto group, amino group, hydroxyl group or a hydrocarbon chain with 1 to 8 carbon atoms containing one or more of the functional groups as an end group.

A photosensitive polyimide composition; the composition comprises a base agent and a curing agent comprising a photoinitiator. By applying an aliphatic diamine monomer, which has a long carbon chain, and a grafting monomer, which has a main carbon chain having a double bond and an epoxy group at two ends respectively, to a method of making the base agent, a mixture of the base agent and the curing agent can be screen printed to form a photosensitive polyimide film on a copper foil. Also, the photosensitive polyimide film can be exposed under low exposure energy, and can be developed to a solder-resistant polyimide thin film by a weak alkaline developer after exposed. In addition, the solder-resistant polyimide thin film has low dielectric constant, low dielectric loss, good flame resistance, good solder resistance, and good pencil hardness. Accordingly, the photosensitive polyimide composition is applicable to high density flexible printed circuit boards.

The invention discloses a lead-free soldering-resistant full-silver conductive paste, comprising the following components by weight percent: 80-85wt% of globular silver powder, 5-12wt% of organic solvent, 3-6wt% of macromolecule resin and 1-7wt% of lead-free glass powder, wherein the appearance of the globular silver powder has the characteristics of high roundness, good dispersibility, moderate contractibility and specific surface of 0.1-2.0m<2> / g; the organic solvent is one or several of alcohol solvents, esters solvents and ethers solvents; the macromolecule resin is one or several of ethocel, hydrogenated rosin resin and polyurethane resin; and the lead-free glass powder is of a CuO-B2O3-SiO2-Bi2O3 glass system. The paste has the advantages of green environmental protection and low cost. The paste can be applied to thick-film network array resistors, with good solderability, soldering resistance, surface compactness and tin coating planeness.

One of major objects of the invention is to provide an epoxy resin composition and a semiconductor device exhibiting good soldering resistance when being formed on a non-copper frame. Thus, this invention provides an epoxy resin composition for encapsulating a semiconductor comprising (A) an epoxy resin, (B) a phenolic resin, (C) a hardening accelerator, (D) an inorganic filler and (E) a triazole compound, preferably an epoxy resin composition for encapsulating a semiconductor wherein the triazole compound is a compound represented by general formula (1): wherein R1 represents hydrogen atom, or mercapto group, amino group, hydroxyl group or a hydrocarbon chain with 1 to 8 carbon atoms containing one or more of the functional groups as an end group.

The invention relates to electrode slurry and a preparation method thereof. The electrode slurry comprises the following components in percentage by weight: 25% to 75% of spherical copper powder, 0 to 40% of flake copper powder, 3% to 12% of glass powder and 13% to 32% of an organic binding agent, wherein the glass powder belongs to a ZnO-B2O3-SiO2-BaO glass system. The electrode slurry is lead-free, environment-friendly, and lower in sintering temperature.