Untersuchungen des Schichtwachstums im Co(W)-Zn-System
Research output: Thesis › Master's Thesis
Nowadays, many different elements, especially metals, are used in high-quality products. At the end of their service life they constitute as a raw material source and should be reintegrated into the material cycle. By recycling these residues a conservation of primary deposits, especially of critical elements, can be achieved. For example, metals like tungsten and cobalt compromises the main elements in hard metals. For their production highly pure powders of Co and WC are used, which are converted into a compact form by liquid phase sintering. In this case, a part of the WC or W dissolves in Co and forms different phases. The aim of this work is to investigate the influence of dissolved W in the Co (W)-Zn system to analyze the behavior of the individual elements. For simplicity, raw materials of pure Co and W were used. Contacting these materials with liquid zinc and holding at certain temperatures gives an insight to the influence of various process parameters on the formation of intermetallic Co-Zn-phases. The results show, that W diffuses from the base material through the intermediate layer and accumulates at intermetallic Co-Zn-phases to form compact or grainy and thin enrichments. Varying the parameters temperature, time and W-contents can influence the effect of W on the layer growth. The outcomes indicate that lower temperatures have a negative influence to the layer growth. Increasing temperatures and W-content have a positive effect and lead to higher thicknesses of the intermetallic phases. This can be attributed to the fact that the formed intermetallic Co-Zn-phases and also Zn have no solubility for W, which gets replaced to the outside of these phases.