The purity of the high pure silver target is 4N5 ~ 5N, the microstructure of the high pure silver target is a fine uniform grain, the average grain size is less than 30μm; The preparation method mainly includes: (1) After the silver ingot is hot forged, a first batch of crystallization annealing is performed to obtain the first blank; (2) After the first billet is treated by static pressure deformation, the second billet is obtained by rolling; (3) The second blank is annealed by a second recrystallization to obtain the high sterling silver target. The high pure silver target of the invention has no defect, the film thickness is uniform after PVD coating on the liquid crystal display, and the yield of the liquid crystal display is greatly improved.
The silver raw material with purity above 4N is selected, and the silver raw material is melted by atmospheric melting or vacuum melting method, and the molten soup is cast, and then cooled to form the ingot billet. The ingot billet is immediately subjected to thermal insulation heat treatment, and the thermal insulation is homogenized in the temperature range of 400 ~ 900℃, the holding time is more than 0.5h, and then the silver billet is formed by hot rolling or air hammer forging. The silver billet is cold-rolled to form a cold-rolled billet, and the cold-rolled billet is annealed for heat treatment, and the annealing temperature is 350 ~ 700℃, and the time is 0.5 h ~ 3 h, to obtain the silver target billet, and finally the large-size silver target can be obtained by machine processing.
First of all, the stainless steel is processed according to the customer's requirements, and then the brown corundum is sandblasted and the Cu-Al wire is used for the bottom layer, the thickness of the bottom layer is 0.5 mm. Then Laval nozzle made of tungsten carbide alloy is used to spray silver powder. The nozzle structure designed by tungsten carbide is shown in Figure 1. Silver powder is spherical powder with particle size of 5 ~ 45 microns, nitrogen pressure of 3 ~ 5Mpa, nitrogen heating temperature of 400 ~ 500℃, and powder feeding speed of 6RPM. The particle speed is increased to 600 ~ 800m/s by accelerating the particle twice through the Laval nozzle. The silver target prepared by cold spraying has the advantages of simple process and dense structure. The relative density of the target can reach more than 99.8%, and the internal grain structure of the target is uniform and fine. Moreover, the deposition efficiency is high and the production cost is reduced.
The high pure silver target and its preparation method and use, by adding the steps of static pressure deformation treatment and recrystallization annealing to the existing silver target preparation method, the internal grains of the silver target become fine and evenly distributed; The preparation method has simple process, low cost and is suitable for industrialization and popularization.
