42results about How to "Improve thermal fatigue life" patented technology

A power semiconductor module and an inverter apparatus in which a device or a joining part is not mechanically damaged even when the temperature in use becomes a high temperature in the range of 175 to 250° C., resulting in excellent reliability at high temperature retaining test and thermal cycling test. Low thermal expansion ceramic substrates are disposed above and below the device. A material having a coefficient of thermal expansion of 10 ppm/K or less is disposed between the ceramic substrates. In addition, an inorganic material having a coefficient of thermal expansion in the range of 2 to 6 ppm/K or less is disposed around the device.

The invention relates to a Fe-Al inter-metallic compound Al2O3 ceramic complex coating and the preparation method thereof, which is characterized in that the Fe-Al inter-metallic compound Al2O3 ceramic complex coating is arranged on a steel base material surface, the total thickness of the coating is between 0.1 mm to 2 mm, the thickness of a micro-arc oxidation Al2O3 ceramic coating is between 50 to 200 Mum. A hot spray method is adopted, an aluminized coating is obtained in the steel base material (electrode) surface, FeAl2 and FeAl phases are formed by reacting in the interface between the aluminized coating and a die cavity surface as well as in the aluminized coating after heat treatment, and a metallurgical bonding is generated between the coating and the die cavity; after the micro-arc oxidation treatment, a Al2O3 ceramic film layer is obtained on the coating surface. The hardness of the ceramic complex coating can reach more than 1200 HV, and the bonding strength between the complex coating and the die cavity reaches more than 250 MPa, and the abrasive resistance is three times of the W18 Cr 4 V steel (64 HRC), and the heat fatigue life is raised more than twice than H 13 steel (47 HRC). The Fe-Al inter-metallic compound Al2O3 ceramic complex coating and the preparation method thereof can be widely used for the surface treatment of die cast dies and the restoration of failure moulds in the die cavity because of abrasive oversize, and can prolong the service life of the die cast dies.

In order to inhibit the connection failure due to the degradation of the connection interface strength of the electrode pad and the warp thereof in the semiconductor device having an electrode pad, a metal layer formed on the electrode pad, and a metal bump formed on the metal layer, in the present invention, gold (Au) is contained in the metal layer, the metal bump is made of solder mainly made of Sn and designed to have an average height H of 100 μm or less per unit area in the electrode pad, and the concentration of Au of the metal layer dissolved in the solder is set to 1.3×10⁻³ (Vol %) or less. More preferably, the metal bump contains palladium (Pd), and the solder coating for forming the metal bump on the electrode pad is performed by using the dipping and the paste printing in combination.

The invention relates to a laser surfacing modification method for a thermal barrier coating. The method comprises the following steps of: firstly, carrying out washing and sand blasting on the surface of a base body; then, preparing the thermal barrier coating in a thermal spraying state on the surface of the base body; then, designing shape, size, arrangement rule and distribution density of laser modification unit bodies in a pile nail structure to be prepared in the thermal barrier coating; then, adjusting the process parameters of a laser according to a design model; then, performing laser modification to the thermal barrier coating; and finally, performing the stress relief annealing treatment to the laser modified thermal barrier coating. With the adoption of the method for arranging discontinuous and dispersed intensifying unit bodies in the pile nail structure in the thermal barrier coating, the thermal barrier coating can not only generate characteristic of soft and hard alternate change, but also generate the 'pinning effect', thus not only relieving stress concentration at the crack tip of the coating and reducing the crack rate of the coating, but also extremely improving the bonding strength of the coatings, prolonging the thermal fatigue service life of the thermal barrier coating, improving the tissue structure of the coating and improving the compactness of the coating.

The invention provides a method for building an SMT welding spot IMC thermal fatigue probability failure physical model. The method includes the following steps of determining an IMC growth physical model, (2) determining a physical model of the relation between SMT welding spot thermal fatigue service life and IMC thicknesses, and (3) determining IMC thickness distribution probability density function mu (delta). After the preceding three steps are carried out, by means of intermetallic components, namely the bond IMC, the function relation between SMT welding spot reliability and the SMT welding spot machining process and between SMT welding spot reliability and work conditions is directly built; considering dispersion of the IMC thicknesses, discretization is carried out on different products or identical products of different batches, and the SMT welding spot IMC thermal fatigue probability failure physical model is built. According to the method, the relation between the SMT welding spot reliability and process conditions is directly built, and bases are provided for improving the production welding process, the SMT welding spot work environment, prolonging SMT welding spot thermal fatigue service life and improving reliability of welding electronic products.

A semiconductor device includes a semiconductor chip having a current path between a first principal surface and a second principal surface opposite from the first principal surface, a first conductive frame having an opposite region to the first principal surface, and a second conductive frame electrically connected via electrical connection member to a pad formed on the second principal surface. In a gap between the first principal surface and the first conductive frame, there are arranged multiple column-shaped lead-free solders which are arranged within a circle drawn around a center of the opposite region and having a diameter corresponding to a narrow side of the opposite region, and which electrically connects the first conductive frame with the semiconductor chip, and a filler which is filled between the multiple column-shaped lead-free solders.

A semiconductor device comprises a semi-conductor chip bonded on a top surface inside a case electrode by a bonding material and a lead electrode bonded on a top surface of the semiconductor chip by a bonding material with a space of the case electrode filled with an insulating material for sealing the bonded sections, wherein a groove is provided on a top surface of the case electrode from an edge of the semiconductor chip, to thereby reduce heat distortion which is generated on a large scale at an end of the bonding material on account of a difference in coefficients of linear thermal expansion between the semiconductor chip and the case electrode and improve the thermal fatigue life.

An automobile exhaust system hot end support is used for being connected with a three-way catalyst shell. The automobile exhaust system hot end support comprises a support body, a strap and a fastening bolt, wherein the strap surrounds the three-way catalyst shell to be connected with the fastening bolt into a hoop, and the fastening bolt penetrates through the support body to be connected with the two ends of the strap so that the support body can be fixed to the three-way catalyst shell. Due to the fact that the support is directly connected with the three-way catalyst shell, the problem that the space in an engine cabin is small is effectively avoided. Due to the fact that the support is directly connected to the three-way catalyst shell and is very close to an engine cylinder block, the rigidity of the whole system is effectively improved, the first-order frequency of the system is increased to be higher than 200 Hz, resonance of an engine within 6000 RPM is avoided, and the fatigue life of the whole system is effectively prolonged.

A re-melted and hardened natural gas engine aluminum alloy piston comprises a piston body and a top combustion chamber. An annular re-melted and hardened layer is arranged at an arc corner of the bottom of the combustion chamber, the cross section of the re-melted and hardened layer is a circular arc, the particle size of a metallographic structure primary silicon phase and an intermetallic phase of a reinforced annular area is 1/4-1/10 that of a non-re-melted portion of a matrix after the arc corner of the bottom of the combustion chamber of the piston is re-melted, so that the thermal fatigue resistance of the piston is improved, mechanical load and thermal load generated in operation of an engine are more reliably borne, thermal fatigue resistance experiment results indicate that the thermal fatigue resistance life of the reinforced annular area can be prolonged by about 2-5 times, and the service life of the piston is greatly prolonged in practical use.

A diesel engine integral cylinder cover with air valves arranged in parallel comprises a cylinder cover body, an air inlet channel and an air exhaust channel, and the air inlet channel and the air exhaust channel are arranged in the cylinder cover body. One side of the cylinder cover body is an air inlet side end face with an air inlet channel opening, and the other side of the cylinder cover body is an air exhaust side end face with an air exhaust channel opening. The cylinder cover body is of a multi-cylinder and one-cover integral structure. The part, corresponding to each cylinder, of a cylinder cover bottom surface is provided with two air inlet valve holes, two air exhaust valve holes and an oil injector hole. The air inlet valve holes are close to the air inlet side end face, and the center connection line of every two air inlet valve holes is parallel to the air inlet side end face. The air exhaust valve holes are close to the air exhaust side end face, and the center connection line of every two air exhaust valve holes is parallel to the air exhaust side end face. Two bolt holes are formed in the position, between flame face sealing tapes of every two adjacent cylinders, of the cylinder cover bottom surface, and an unload groove is formed between every two bolt holes. According to the diesel engine integral cylinder cover with the air valves arranged in parallel, the flow capacity of the air channels is high, and the thermal fatigue resistance is good.

The invention discloses a circuit board with a digital signal isolation circuit chip and a packaging method. The circuit board includes a substrate and one or a plurality of digital signal isolation circuit chips, wherein the digital signal isolation circuit chip is packaged on the substrate through a flip-chip bonding mode. The flip-chip bonding packaging technology is adopted in a digital signal isolation circuit, and therefore, problems caused by bonding and interconnection can be greatly reduced, and the reliability of the chip can be improved.

The invention discloses a brake disc based on Bayesian inference and an optimization design method.The brake disc comprises a brake disc inner disc face, the brake disc inner disc face is of a scraggly gradually-changing curved surface structure in the radial direction, and the gradually-changing curved surface structure comprises a middle arc-shaped outer convex face protruding outwards; the method comprises the following steps: taking R1, R2, R3, L1 and L2 as design variables, selecting a satisfactory average Mises stress of the brake disc surface as an observation value, and calculating the average Mises stress of the brake disc surface according to the average Mises stress of the brake disc surface, the average Mises stress of the brake disc surface, the average Mises stress of the brake disc surface, the average Mises stress of the brake disc surface and the average Mises stress of the brake disc surface, and the average Mises stress of the brake disc surface and the average Mises stress of the brake disc surface. The design variables are reversely optimized based on the Bayesian inference theory, information updating of the design variables is achieved, and finally the optimal solution of the design variables is determined; the internal heat dissipation area is increased, the heat dissipation capacity of the brake disc is improved, the brake disc structure has good heat crack resistance, the thermal fatigue life of the brake disc can be prolonged, and the brake safety of a vehicle is improved.