Method for improving tungsten-base gold-plating bond strength

Abstract

The invention relates to a method for improving the gold-plating bond strength of a tungsten metal surface, and belongs to the field of the surface modification of metal materials. In the method, the problems of dropping and delamination of plated gold on surfaces of tungsten materials are solved. The method comprises the following steps of: removing oxides on the surface of a tungsten spiral line before electroplating; electroplating copper at the temperature of between 20 and 60 DEG C and under a condition that the pH value is between 0.6 and 1.2 and a condition that the current density is between 0.1 and 0.3 A / dm<2> for 15 to 120 seconds, wherein copper layer electroplate liquid comprises 170 to 210 g / L of anhydrous cupric sulfate, 35 to 60 g / L of sulfuric acid and the balance of water, and the pH value is regulated by the sulfuric acid and sodium hydroxide; and electroplating the gold at the temperature of between 20 and 35 DEG C under a condition that the pH value is between 8 and 11 and a condition that the current density is between 0.4 and 0.6 A / dm<2> for 150 to 300 seconds, wherein gold-plating liquid comprises 5 to 8 g / L of gold sodium sulfite, 30 to 40 g / L of anhydrous sodium sulfite and the balance of water, and the pH value is regulated by the sulfuric acid and the sodium hydroxide. In the method, gold-plating samples are subjected to heat treatment in a hydrogen furnace at the temperature of between 950 and 1,000 DEG C for 30 minutes, and gold-plating layers are not dropped.

Description

technical field [0001] The invention belongs to the technical field of surface modification of metal materials and provides a method for enhancing the bonding strength of gold plating on the surface of tungsten metal to solve the problems of peeling off and peeling of gold plating on the surface of tungsten materials. Background technique [0002] TWT helix materials are required to have the characteristics of high melting point, high electrical conductivity, high thermal conductivity, and high hardness. At present, metal tungsten or molybdenum is mainly used. However, due to the high resistivity of tungsten and molybdenum, the high-frequency loss is large, resulting in an increase in operating temperature, which seriously affects the stability and reliability of the TWT. In order to reduce the high-frequency loss on the surface of the helix, the method of plating the surface of the helix with a thin film material with high thermal conductivity and low resistivity, such as c...

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Problems solved by technology

[0003] In order to solve the problem of the binding force between the gold-plated layer and the surface of the spiral wire, the present invention starts with the electroplating process and provides a method for enhancing the strength of the gold-plated bonding force on the surface of tungsten metal. In this way, a gold-plated layer that is firmly combined with the surface of the tungsten spiral wire is obtained. layer, and after the gold-plated sample was heat-treated in a hydrogen furnace at 950°C to 1000°C for 30 minutes, it was found that the gold-plated layer did not fall off or peel.

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