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1·Fuse potassium dichromate (19) in a porcelain crucible.

在瓷坩埚中熔化重铬酸钾(19)。

2·A porcelain crucible was heated to a dull red color, placed on the test material, and allowed to cool to ambient temperature.

将置于所测试材料表面的陶瓷坩埚，加热至暗红色然后让其冷却，温度降至室温。

3·Test a: porcelain crucible? A porcelain crucible was heated to a dull red color, placed on the test material, and allowed to cool to ambient temperature.

测试a：陶瓷坩埚。将置于所测试材料表面的陶瓷坩埚，加热至暗红色然后让其冷却，温度降至室温。