Direct preparation of Fe-TiC composite powders and its ceramics by vacuum carbothermal reduction
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
In traditional route to produce TiC-type steel-bonded carbides, steel powder and TiC powder are mixed mechanically and sintered after pressing. The cost of the raw materials in this method is high, and the surface of TiC powder is easily oxidized which makes the wettability between TiC and Fe terrible in following powder metallurgy process. The terrible wettability makes it difficult for Fe to combine tightly with TiC, seriously affecting the properties and purity of the product. The present experiment uses titanium dioxide powder, graphite powder and reduced iron powder to produce Fe-TiC composite powder by vacuum carbothermal reduction firstly, and then the composite powder is used to produce TiC-type steel-bonded carbides. This route successfully avoids the surface oxidation of TiC powder and has the advantages of low cost of materials, high purity of the products and excellent properties of the prepared ceramics. The results indicate that, with the increase of carbon ratio in the raw materials, the hardness of the product decreases while the bending strength increases firstly and then decreases. Besides, the addition of Ti powder enhances the hardness and bending strength of products. The optimal product with a hardness of 11.7 GPa and a bending strength of 1 776 MPa is obtained when the raw material ratio TiO2:C:Fe is 20:8.6:15, temperature is 1 400℃ and holding time is 6 h with Ti powder of a mass fraction of 1% as the additive.
