Research On Preparation And Properties Of W-Cu Metal Slurry And Its Casting Films

W-Cu composite materials are extensively applied in dynamic high pressure, electronic industry and energy field. For example, there has been a large gap between W and Cu density in W-Cu FGMs that makes it one of the preferred systems. Because it expands density range of density gradient materials and becomes an important part for Dynamic high pressure research. Furthermore, W-Cu graded materials is also an ideal heat sink material with good thermal conductivity and low thermal expansion because of W materials'high melting point, low expansion, high strength and Cu materials' high thermal conductivity. Tape casting has become one of the preferred methods about preparation of W-Cu composites as a result of its simple procedure, low cost, high efficiency and materials'composition being precisely controlled.Preparation of W-Cu slurry and films is the key of fabricating W-Cu composite materials by tape casting. W-Cu composite materials' property depends largely on the merits of casting film. Therefore, this thesis is aimed to prepare slurry with high performance for tape casting and accomplish casting films meeting requirement of composite materials molding.This paper used polyvinyl butyral (PVB) and poly methyl methacrylate (PMMA) as a binder respectively, Hypermer KD-1 as a dispersing agent and polyethylene glycol (PEG) as a plasticizer for preparation of W-Cu metal slurry that needs metal powder and organic reagent mixing by twice-milling. As shown in the survey, the viscosity of slurry increases with metal powder content or binder content's augment. When the binder PMMA's amount only attains 4wt%, W-Cu metal slurry with 80wt% solid content can be prepared and its viscosity is 467.7 mPa·s.When the binder PVB's amount only attains 3wt%, W-Cu metal slurry with 65wt% solid content can be prepared and its viscosity is 1233 mPa-s. When the PMMA content is 4wt%-5wt% or PVB amount is 4wt%-5wt%, W-Cu slurry's stability factor DC＞0.9 that indicates good stability.The fluid model of prepared slurry is in accordance with Herschel-Bulkley and the slurry is suitable for tape casting because of its moderate viscosity, shear thinning character and time independence. All of these have laid a good research base for W-Cu composite films' preparation.In the thesis W-Cu casting membrane with different components can be acquired after bubbling off, tape casting and drying at constant temperature. And its structure and properties are studied. As shown in the survey, metal particles are closely coated in the W-Cu casting films with PVB as a binder while there are a lot of holes in the W-Cu casting films with PMMA as a binder. The former has high tensile strength and both can be processed. The W-Cu films'surface is well-proportioned with 4.0wt% PVB content or 4.0wt% PMMA. When PVB or PMMA content attains or excess 4.0wt%, the films are symmetrical from top to bottom. The density of W-Cu casting films with PMMA as a binder is higher than films with PVB as a binder and the density first increases and then decreases with the binder content increasing. The prepared films' thickness is well-distributed. The average error between theoretical thickness calculated by H-B model and experimental data is 5.5% and the maximal is less than 10%.