Effect of Dry and Wet Ball Milling Process on Critical Powder Loading and Mixture Properties of Fine WC-10Co-0.8VC Powder

Abstract

Micro powder injection molding (μPIM) has great potential for the production of micro cemented carbide parts that require high hardness and toughness. The main stages of the μPIM process include mixing the powder and organic binder, injecting, debinding, and sintering. High critical solid loading of submicron tungsten carbide (WC) powder is one of the requirements in the micro powder injection molding process, which is not obtained easily. This paper investigates the effects of ball milling on critical solid loading of submicron WC. Dry and wet ball milling processes were used to prepare a powder mixture with composition of WC-10Co-0.8VC (wt-%). Critical powder volume concentration (CPVC) was determined using the torque variation method, and the powder characteristics were assessed using scanning electron microscopy and energy dispersive X-ray spectroscopy. CPVC was at 42% and 50% for the dry and wet ball milling processes, respectively. Apparent and tap densities of the powder mixture were achieved at 2.4 g/cm3 and 2.96 g/cm3 after dry milling and at 2.54 g/cm3 and 3.39 g/cm3 after wet milling, respectively. Wet ball milling causes fine particles to de-agglomerate and improves the critical solid loading, which is advantageous for submicron cemented tungsten carbide injection molding. The homogeneity of the powder mixture can improve under longer time of wet milling process and it can be expected that reduce microstructure defects in sintered components.

The Effect of Surface Treatment with Isocyanate and Aromatic Carbodiimide of Thermally Expanded Vermiculite Used as a Functional Filler for Polylactide-Based Composites

“…This is confirmed by the SEM images shown in Figure 5 . The largest share of the smallest filler particles was recorded for W-KI, which may result from a change in the process conditions (i.e., the wet process’s implementation [ 54 ]), which results from the low KI melting point. Considering the increased fraction of the smallest particles, in the range below 0.1 µm, it can be assumed that the addition of the filler caused organofunctionalization of the expanded vermiculite and an additional intercalation of its structure.…”

“…This is confirmed by the SEM images shown in Figure 5. The largest share of the smallest filler particles was recorded for W-KI, which may result from a change in the process conditions (i.e., the wet process's implementation [54]), which results from the low KI melting point.…”

Study of the Processing of a Recycled WC–Co Powder: Can It Compete with Conventional WC–Co Powders?

“…Samples have been dried in an oven at 100 °C for 12 h. Zinc stearate was chosen as a dry milling medium. Zhang et al [39] have shown that the dry milling conditions allow the obtention of smaller grains in agglomerated particles while wet milling provides better dispersion of the particles [42].…”

“…Ball milling is widely used in tungsten carbide preparation to ensure a good homogenization of the different powders as well as to induce "mechanical alloying" [37,38]. The influence of ball milling parameters (medium, balls diameter, time) has been studied in different papers [39][40][41][42][43][44].…”

Critical Powder Loading and the Rheology of Nanosized Cemented Carbide with Titanium Carbide as Grain Growth Inhibitor for Injection Molding

“…Therefore, with a great technique and cost advantages, powder injection molding (PIM) is the most suitable method to produce complex shapes of cemented carbide components [2]. Basically, PIM was adjusted from metal injection molding process (MIM) [3]. MIM process consists of four main steps: mixing, injection molding, debinding, and sintering.…”