Fired Silver Paint: Precipitated Silver and Flux in Polyvinyl Alcohol with Ammonia (Gray, Erie Resistor 1954, Ex. 1)

A paint for putting silver electrodes on ceramic, glass or mica. Fine silver powder and a little ceramic flux are held in polyvinyl alcohol dissolved in water, with a trace of ammonia to make the wet paint conduct. So a capacitor can be measured while it is being painted. On firing, the silver becomes a film held on by the flux. The silver settles, so stir while painting. Source: Robert B. Gray, US 2,695,275 (Erie Resistor, 1954), Example 1. Not given: how the silver was precipitated, which flux, the form of the ammonia, and the firing heat. Ours: precipitated silver made by reducing silver chloride with zinc, bismuth subnitrate as the flux (one Gray names), and strong ammonia water. Picture drawn by Youblob.

初学者

1 day

说明

Dissolve 4 g polyvinyl alcohol in the water

For 100 g of paint: dissolve 4 g polyvinyl alcohol in the water, warming it to help it dissolve. The water is the balance, about 35 to 44 g. Warming is ours.

此步骤所需材料：

聚乙烯醇粉末4 克

蒸馏水1 as required

所需工具：

等臂天平

硼硅玻璃烧杯

电热板

硼硅玻璃棒

Grind in 50 g precipitated silver and the flux

Grind 50 g precipitated silver and 2 to 10 g ceramic flux into the solution until smooth. Gray allows some silver chloride left in the silver. Ours: silver from the zinc route, and bismuth subnitrate, one of the fluxes Gray names. The right amount of flux depends on the ceramic.

此步骤所需材料：

沉淀银50 克

次硝酸铋1 as required

所需工具：

等臂天平

研钵与研杵

丁腈手套

Add 0.2 to 1 % ammonia

Stir in ammonia, 0.2 to 1 % of the paint. It evaporates from the film but makes the wet paint conduct. Ours: added as strong ammonia water. Sharp fumes: work in air, goggles.

此步骤所需材料：