History of Ceramic Foam Filtration. (Aluminum Silver Anniversary Paper).In his Silver Anniversary Lecture titled, "Clean Castings Through Ceramic Foam Ceramic foam is a tough, plastic-like foam made from ceramics. It is similar to Kevlar.The foam is made of aluminum oxide, a common high-temperature ceramic, but gets its extraordinary insulating powers from the many tiny air bubbles within the material. Filtration," F. Mollard, Mollard Consulting, gave a historical look at the development of ceramic foam filtration over the last 25 years. According to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. Mollard, there are a great deal of benefits to ceramic foam filtration in aluminum castings. These include a reduced scrap rate, increased yield, enhanced level and consistency of mechanical properties (primarily ductility ductility, ability of a metal to plastically deform without breaking or fracturing, with the cohesion between the molecules remaining sufficient to hold them together (see adhesion and cohesion). Ductility is important in wire drawing and sheet stamping. , yield strength and fatigue resistance), and improved surface finish characteristics and machinability. While initial applications of ceramic foam filters were for sand castings, they have now broadened to include permanent mold, plaster and ceramic investment castings. Other casting benefits include: * several reliable commercial suppliers; * conductivity with all major aluminum casting alloys; * ability to perform in-mold filtration in combination with filtered primary ingots, as well as crucible crucible, vessel in which a substance is heated to a high temperature, as for fusing or calcining. The necessary properties of a crucible are that it maintain its mechanical strength and rigidity at high temperatures and that it not react in an undesirable way with formation, to achieve optimum cleanliness Cleanliness See also Orderliness. Cleverness (See CUNNING.) Berchta unkempt herself, demands cleanliness from others, especially children. [Ger. Folklore: Leach, 137] cat continually “washes” itself. and mechanical properties; * current availability at ceramic foam compositions including a variety of refractory refractory Material that is not deformed or damaged by high temperatures, used to make crucibles, incinerators, insulation, and furnaces, particularly metallurgical furnaces. aggregate/bonding materials tailored to consumer specifications; * the replacement of early chromite chromite (krō`mīt), dark brown to black mineral. It is an iron-chromium oxide, FeCr2O4, with traces of magnesium and aluminum. bonded ceramic foams by environmentally benign and stronger refractory compositions. Mollard also sees many possible future markets for ceramic foam filters, including diecasting and semi-solid casting. The use of computer-aided analysis of aluminum flow could lead to inclusion retention to optimize filter porosity, shape, size and placement. "The technology for producing clean aluminum castings through ceramic foam filtration has considerably matured since its initial introduction in the 1970s," Mollard said. "This progress is attributable to the sustained efforts of many individuals and organizations and an interdisciplinary approach involving primarily foundry metallurgists and ceramic engineers." |
|
||||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion