Ammonium Hydrogen Carbonate with High Quality

• CAS No.: 1066-33-7
• Color: White
• Appearance: Powder
• Transport Package: Paper
• Specification: large
• Trademark: china
• Model NO.: E1422
• Origin: China
• HS Code: 2930400000
• Production Capacity: 5000kg/Year

Product Description

NaCl is by no means the only space holder used. Carbamide (urea) and ammonium hydrogen carbonate are frequently employed. These are not removed by dissolution as NaCl is, but can be removed by treatments at high temperature (either before sintering, or as an initial step in the sintering heat treatment). Methods using these space holders were developed at around the same time as the SDP, principally for producing higher melting point metals with porosity. The same procedures of blending (often using a solvent) and pressing powders, substituting ammonium hydrogen carbonate and carbamide for NaCl, have been used for titanium and magnesium foams (Bram et al., 2000; Wen et al., 2001, 2002a, 2002b, 2004; Zhuang et al., 2008; Niu et al., 2009; Nouri et al., 2010; Tuncer et al., 2011), superalloys (Bram et al., 2000; Mi et al., 2009), stainless steel (Gulsoy and German, 2008) and copper foams (Hakamada et al., 2007), and examples have also been reported of polypropylene carbonate (PPC) (Hong et al., 2008) and starch being used for titanium (Mansourighasri et al., 2012). All of these are removed by a thermal treatment before sintering, which is effective in retaining the porous shape, even though they decompose at relatively low temperatures (around 200 °C).

Carbamide is also a popular space holder for aluminium (Jiang et al., 2005a) and has been used for stainless steels, not being removed thermally, but by water leaching (Bakan, 2006). Carbamide particles are available in different shapes, as either rough spheres or high aspect ratio flakes. The use of different forms of carbamide allows the pore shape to be controlled as this shape is preserved in the porous material (Bram et al., 2000; Jiang et al., 2005b).

Another important space holder is potassium carbonate, K₂CO₃ (Zhao et al., 2005) and its use is sometimes called the lost carbonate process. This has the advantage that it is thermally decomposed, so an additional leaching treatment is not required. It also is not removed until high temperatures (891 °C, when it melts and decomposes simultaneously (Zhao et al., 2005)), meaning that it can contribute to structural integrity up to high temperatures. This has been used for higher melting point metals, such as copper (Zhao et al., 2005; Thewsey and Zhao, 2008; El-Hadek and Kaytbay, 2008) and iron (Ma et al., 2006).