Preparation method of potassium-containing round-tungsten-doped aluminum strip

Abstract

The invention provides a preparation method of a potassium-containing round-tungsten-doped aluminum strip, comprising the following steps of: carrying out material selection of ammonium paratungstate, carrying out light hydrogen reduction on the ammonium paratungstate, carrying out AKS (Adjacent Key Suppression) doping, directly reducing, carrying out acid washing, preparing powder, carrying out cold isostatic compaction, pre-sintering, vertically smelting and the like. According to the invention, ammonium paratungstate with a special Fisher granularity is selected to carry out the light hydrogen reduction; and after the doping, a special process is used for directly reduction to obtain rough and fine tungsten-doped powder. Meanwhile, mixed tungsten powder which is good in normal distribution and simultaneously avoids a peak-shaped or double-peak phenomenon is obtained according to a reasonable rough and fine powder proportion; the tungsten powder is pressed into a tungsten blank strip; the tungsten blank strip is pre-sintered to form a tungsten strip which is primarily and vertically smelted at a high temperature; and the quantity of particles on the section of the tungsten strip is increased according to a potassium foam forming mechanism and the partial growth of crystal grains is avoided, so that the aims of small potassium foam hole diameter, large density, a plurality of crystal interfaces, long potassium foam row and uniform distribution are achieved. A tungsten filament for a halogen tungsten lamp, which is obtained by machining the obtained tungsten strip through a pressure, is re-crystallized to obtain a dovetail overlap joint structure with a good tissue; and the length / width ratio of the potassium foam is great and the high-temperature anti-drooping performance is good.

Description

technical field [0001] The invention belongs to a preparation method of dense, high-purity and special tungsten material, in particular to a preparation method of potassium-doped round tungsten-aluminum bar. Background technique [0002] Potassium-doped round tungsten aluminum rod is the raw material for manufacturing high-temperature heating elements and high-temperature-resistant components such as electric light sources, anti-sagging tungsten wires in electronic devices, and vacuum-sprayed tungsten hinge wires. Doped tungsten rods produced by conventional processes have various defects and are only suitable for the production of ordinary tungsten wires, resulting in low yields and high production costs. For example, the patent No. CN03124646.X, in this method, the doped blue tungsten is directly reduced to doped tungsten powder, and the reduction is not divided into coarse and fine particles. The powder after batching has a poor normal distribution, and there are spikes o...

AI Technical Summary

Problems solved by technology

Doped tungsten rods produced by conventional processes have various defects and are only suitable for the production of ordinary tungsten wires, resulting in low yields and high production costs.

For example, the patent No. CN03124646.X, in this method, the doped blue tungsten is directly reduced to doped tungsten powder, and the reduction is not divided into coarse and fine particles. The powder after batching has a poor normal distribution, and there are spikes or The bimodal phenomenon leads to the existence of cross-sectional crystallization and uneven distribution of potassium in the product, low product density, poor performance of subsequent processing and subsequent products, etc.

In addition, the control pressure for pressing the billet is only 20-28MPa, the strength of the billet is still very low, and it has not been pre-sintered, so it is very easy to cause fractures and damages during the vertical melting and sintering process

The patent application number is CN200510021838.X. This method adopts one or two reduction treatments, and carries out intermediate frequency sintering on the tungsten strips after vertical melting and sintering, which has the disadvantages of long production process, high energy consumption and high cost.

The patent application number is CN200610002610.0. This method does not pickle the doped tungsten powder. Although a sufficient amount of potassium is retained, a considerable part of silicon, aluminum and other harmful elements are also retained. When this part of harmful elements and Part of the potassium element will leave a large number of voids after volatilization during the vertical melting and sintering process, resulting in defects such as uneven crystallization and low density in the section of the tungsten rod product

At the same time, this method also adopts the secondary reduction process, which has the disadvantages of long production process, high energy consumption and high cost.

In addition, the pressed billets are not pre-sintered, resulting in the disadvantages of tungsten bars that are easily broken and damaged during vertical melting and sintering.

The patent application number is CN201110125548.5. This method uses secondary reduction to produce medium and fine particles doped with tungsten powder, which has the disadvantages of long production process, high energy consumption and high cost.

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