Calcium fluoride mechanical properties

Plasma-sprayed, flame-plated, or electrolytically deposited coatings of powders of Al O Ci O TiN, WC, and Ti02 can be applied as wear-resistant ceramics on metal substrates with or without Co, Ni, or Cr incorporated to improve mechanical properties. Silver, barium fluoride—calcium fluoride, and other modifying materials have also been found useful in ceramic coatings for improved friction and wear properties (35). Diamond coatings are also being developed (36). 

In 1961 Hayes and Twidell (8) found that if calcium fluoride crystals containing trivalent thulium were irradiated with x-rays, some of the thulium was converted to the divalent state. This discovery was the first of many in the study of dilute solutions of divalent rare earth ions. Most workers prefer to study the alkaline earth fluorides since these materials are stable with respect to air and have more attractive mechanical properties than the alkaline earth chlorides, bromides, and iodides. Enough work has been carried out in these softer materials to show that reactions similar to those in the fluorides do occur. 

Simmons, C.R., 1%1, The Mechanical Properties of Yttrium, Scandium, and the Rare Earth Metals, in Spedding, F.H., and A.H. Daane eds.. The Rare Earths (John Wiley and Sons, New York), pp. 428-452. a) Lithium-reduced scandium fluoride, distilled and arc-melted into buttons, b) Calcium reduced scandium fluoride in tantalum crucibles contain 2-5 w/o Ta. c) Arc-melted yttrium low value for 500 ppm O and 700ppm F, high value for 2500 ppm O, 3000 ppm F. (500 kg. load, 10 mm indenter.)... 

Tamari, N., Kondoh, I., Mouri, I., and Kinoshita, M. (1988b) Effect of calcium fluoride addition on densiflcation and mechanical properties of hydroxyapatite-zirconia composite ceramics. J. Ceram. 

The particular properties of HF forced the scientific community to understand its mechanism and its lesions kinetics (see Sect. 4.1.2.1). The idea was to find a way to improve the water washing. But the first improvement was to add, after initial decontamination with water, a secondary treatment such as to apply calcium gluconate as an ointment or by intravenous or subcutaneous injection. Topical applications are easier to perform but require repeated ointment based on patient s pain. Hydrofluoric acid bums are very painful. The pain depends on the concentration. If the concentration is higher than 50 %, the sensation of pain is immediate. If the concentration is less than 50 %, the pain and the lesions can be delayed. Calcium gluconate limits the evolution of the bum by binding fluoride ions but has only a light effect on H+ ions. 

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