Slip Casting of Aluminum Oxide*

Abstract

Fused alumina, after being subjected to ball milling and acid treatment, may be suspended in water to form a slip. Deflocculation is obtained by the addition of the proper amount and type of either an acid or a base. Both drain and solid castings can be produced successfully from acidic or basic slips. The casting behavior of the slips and the properties of the cast pieces are summarized for variations in pH and specific gravity, the range of pH being 3.00 to 12.50 and the range of specific gravity, 2.60 to 3.00. Although no extensive investigation of the firing behavior was made, sufficient firing was done to indicate that no special techniques are required.

Colloidal processing: enabling complex shaped ceramics with unique multiscale structures

“…With clays being the catalyst of how colloids and colloidal processing can aid in the formability and properties of ceramic materials, investigation into how to make nonclay ceramics plastic began. As early as 1910 alumina (Al 2 O 3 ) was rendered plastic by acid treatment followed by zirconia (ZrO 2 ) and other ceramics by the mid 1920s . Around this time, colloidal processing found use in the fabrication of dense composite bricks made from thoria (ThO 2 ) and ZrO 2 used primarily as refractory wall liners .…”

“…Thin titanium dioxide (TiO 2 ) sheets were produced for use as capacitors, with the process depending strongly on the suspension properties and, as to be expected, on the apparatus settings. Work carried out by Hauth in 1949 on the slip casting of Al 2 O 3 studied the effect of pH on casting properties such as density, porosity, green strength and others, with suspensions ranging between acidic (3.0) and basic (12.5) pH levels. Most noticeably, the author applied the diffuse double layer theory to describe the charge on the colloidal particles used in the Al 2 O 3 suspensions that was earlier adopted by Johnson and Norton in describing the dispersion of clay slips.…”

“…As early as 1910 alumina (Al 2 O 3 ) was rendered plastic by acid treatment followed by zirconia (ZrO 2 ) and other ceramics by the mid 1920s. 21 Around this time, colloidal processing found use in the fabrication of dense composite bricks made from thoria (ThO 2 ) and ZrO 2 used primarily as refractory wall liners. 22,23 Work carried out by Cox 24 using simple potter's methods such as stoneware turning showed that the addition of colloidal bentonite to traditionally nonplastic clays was able to alter their formability and produce crack-free hollow forms, enabling the use of a wider range of clays on brick and tile machines.…”

Dichte Calciumfluoridkeramik, ein neues, gegen Flußsäure beständiges, feuerfestes Tiegelmaterial

“…5 Eine andere, besondere Eigenschafi dichter Calciumfluoridkeramik ist ihre Bestandigkeit gegenuber Fluor und dessen Verbindungen. Es eignet sich ferner als fester Elektrolyt fur elektrochemische Zellen.…”

Toxic‐Free Aqueous Gelcasting of Alumina Ceramics Using Alumina Sol Binder

“…Although it has moderate coefficient of thermal expansion and low thermal shock resistance, it has been widely used for ceramic radomes application for the missiles, especially for the speed Mach number more than 3 due to its unique physical, electrical, mechanical, and extreme good rain erosion properties . Traditionally, alumina has been fabricated by cold and hot pressing, injection molding, slip casting, and centrifugal casting . Apart from these methods, the newly reported gelcasting process has several advantages over the other methods.…”