Crucibles ceramic

In rocket construction, for the production of metal-melting crucibles, ceramics, as semiconductor... 

Glasses and electrically insulating ceramics can be used as crucibles and are often desirable because of their chemical inertness with many molten materials. Typical crucible ceramics are Th02, BeO, stabilized Zr02 (i.e. additions of Hf02 and CaO to ZrO, AI2O3, MgO, BN, and fused silica. Kohl has written an extensive review of the oxide and nitride materials that may be of interest as crucible materials. The ceramics can be heated by conduction or radiation... 

Transfer the filtrate to a ceramic evaporating dish and heat on a water bath until a crystalline scum forms on the top. Cool the dish quickly then filter the mess on the vacuum Buchner to yield 96g of Methylamine Hydrochloride. Concentrate the filtrate once again to obtain a second crop of crystals, -IQg. Concentrate the filtrate a third time as far as possible using the water bath, then store the dish in a vacuum dessicator loaded with Sodium Hydroxide in the bottom for 24 hours. Add Chloroform to the residue left in the crucible to dissolve out Dimethylamine Hydrochloride (distill off the Chloroform to recover - good stuff) then filter on the venerable old vacuum Buchner funnel to yield an additional 20g of Methylamine Hydrochloride, washing the crystals in the funnel with a small poiiion of Chloroform ( 10mL). 

Gefass-kunde, /. ceramic art. -ofen, m. (furnace containing receptacles), retort furnace, crucible furnace, pot furnace, etc. gefasst, p.p. p.a. see fassen. 

Calcination is performed in crucibles made of platinum or related metals. Tantalum or niobium oxide can be successfully used in the manufacturing of such crucibles. Frolov et al. [505, 506] developed a method for coating various ceramic materials with tantalum or niobium oxide using an optical furnace. 

Beryllium Oxide (Bromellite). BeO, mw 25.01, white amorph powd, mp 2530°, bp ca 3900°, d 3.01g/cc. Sol in coned acids and alkalies. V si sol in w. Prepn is by burning BeC03 at 900° in a Pt crucible to the oxide. It is used in nuclear reactor fuels and moderators as well as in powder metallurgy, ceramics, fuel cells and coatings (see above)... 

The PuFit is then loaded in ceramic (MgO) crucibles, where it is reacted with calcium to form CaF2 and plutonium metal as follows 7J ... 

The reaction is carried out under an inert atmosphere in an open crucible at approximately 830°C. Figure 1 shows typical equipment used for direct oxide reduction. Vitrified magnesium oxide ceramic is commonly used as a container material, but tungsten and tantalum can also be used(3). If the latter are used, CaF2 is added to lower the temperature needed to liquify... 

C, the rate of reaction tends to be self limiting at hydrogen pressures up to 10 torr. The hydriding technique is used to recover metallic plutonium residues clinging to the walls of ceramic crucibles, and can also be used to recover machining scrap if the feed is free of lubricants or oxides. Mulford and SturdyO4) have found the heat of formation for the reaction... 

Boron nitride is one of the most outstanding corrosion-resistant materials. It is inert to gasoline, benzene, alcohol, acetone, chlorinated hydrocarbons and other organic solvents. It is not wetted by molten aluminum, copper, cadmium, iron, antimony, bismuth, silicon, germanium, nor by many molten salts and glasses. It is used extensively as crucible material, particularly for molten metals, glasses and ceramic processing. 

Crucible with sample 2, sample 3, thermocouple (reference crucible not enlarged) 4, gas inlet 5, ceramic support. 

Melting Crucible (Tundish) Material Ceramics/Refractory... 

Crucibles must be suitable for the required experimental conditions with respect to their material, capacity and shape. As in the techniques of the chemical laboratory, crucible materials are selected to avoid the possibility of reaction between crucible and sample material. The main materials used are the precious metals, oxide ceramics, quartz and graphite. The size of the crucible is determined by the volume to be weighed. 

Table 2 shows a compilation of different crucible materials, the working temperatures, atmospheres and some important physical data. Metal crucibles are used more for the investigation of clays, oxides, ceramics, glasses, inorganic materials as... 

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