| The effects of SiC in molten borax on the electro-boronizing have been studied quantitatively and the effects of SiC in molten borax deteriorated by Fe on the electro-boronizing also have been studied. The more the amount of SiC is in the molten borax, the more the boronized depth increases and microhardness of boronized layer increased too. However at the lower temperatures, the more the amount of SiC is in the molten borax, the less the boronized depth is. Because the fluidity of the electrolyte having more SiC content becomes worse at lower temperature. Especially, when the boronizing is carried out in the electrolyte whose composition is 40%SiC and 60%Na₂B₄O_7, Si diffuses into specimen faster than B and forms Fe-Si alloy at the region between boronized layer and matrix and Fe-C layer is also formed in the region by C diffused with B, Si. Therefore, The separation of boronized layer is apt to occur easily, because microhardess of this region is increased. The more the amount of SiC is in the molten borax, the greater the activation is. The molten borax deteriorated by Fe is recovered in ability of boronizing by addition of SiC. |
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