No abstract

Determination of the phase relationships on the Zn3false(PO4)2‐Mg3false(PO4)2 join by the quench method has enabled the previously designated “gamma zinc phosphate” to be identified as a solid solution of zinc orthophosphate in magnesium orthophosphate. Mg3false(PO4)2 takes 95 mole % Zn3false(PO4)2 into solid solution at 1000°C. β‐Zn3false(PO4)2 takes a small amount of Mg3false(PO4)2 into solid solution (about 3 mole % at 1000°) and, in order to satisfy the requirements of the Phase Rule, α‐Zn3false(PO4)2 must take a small amount of Mg3false(PO4)2 into solution. The previously determined Zn3false(PO4)2‐Mn3false(PO4)2 relationships are discussed in terms of the new data for the zinc‐magnesium orthorphosphate system. Solid solution relationships in the system normalMgO‐normalZnO‐P2O5 are diagrammed and discussed.Data on peak emission and brightness of the β‐Zn3false(PO4)2 solid solution and the Mg3false(PO4)2 solid solution were obtained using molar substitutions of manganese as an activator. The brightness of the β‐false(normalZn,normalMg)3false(PO4)2:normalMn solid solutions compares favorably with commercial β‐Zn3false(PO4)2:normalMn phosphors and the N.B.S. standard. The manganese‐activated phosphors near the high zinc end of the Mg3false(PO4)2 solid solution series are very bright relative to the β‐Zn3false(PO4)2:normalMn standard, but they peak near 6280Aå, which may in part account for the higher brightness.

235oxide additions. The former showed R = 0.053; the latter, R = 0.022 when fired a t 1760°C. for 1 hour.The binary compounds L i p . 5AI2O3 and Li20 .A1203 can be formed easily by reaction of pure materials at 150OOC. The ternary compounds peucryptite and p-spodumene and solid solutions involving these two compounds can be prepared by reaction of LiZCOa, Alz08, and SiOz at 130OOc. The thermal expansions of the lithium aluminates are very high, but the expansions of P-spodumene and P-spodumene solid solutions are very low. The compound p-eucryptite is unusual in that it shows a high thermal contraction to 1000°C. Some relations between the expansion data and the crystal structure of the phases given above are discussed. II. literatureI) GO. 5Al20, Kordes2 was the first to present data which indicated that 2 E. Kordes, "Crystal and Chemical Investigations of Aluminum Compounds with Spinel Lattice and of y-FezOs," 2 Krist., 91, 193-228 (1935); Ceram. Abstracts, 17 [a] 84 (1938).

Phase relationships in the system Li2O, B2O3‐B2O3 were studied by the quenching method using twenty compositions. The crystalline phases encountered were (a) Li2O, B2O3, which melts congruently at 849°± 2°C., (b) Li2O.‐2B2O3, which melts congruently at 917°± 2°C., (c) a new compound, 2Li2O‐5B2O3, which melts incongruently at 856°± 2°C. and dissociates below 696°± 4°C., (d) Li2O.3B2O3, which melts incongruently at 834°± 4°C. and dissociates below 595°± 20°C., and (e) probably Li2O.4B2O3, which melts incongruently at 635°± 10°C. Reactions were sluggish at temperatures near 600°C., resulting in metastable relations. Hence phase equilibrium data relating to the lower stability limit of Li2O.3B2O3 and to the upper stability limit of Li2O.4B2O3 are considered to be tentative. Properties of the glasses and crystalline phases were studied. The refractive index of the glasses increased with the addition of Li2O up to 22%, but further additions up to 40% had no substantial effect. Glasses containing less than 30% Li2O were water soluble. Limited data on the density and thermal expansion of the glasses are presented. Li2OB2O3 was euhedral, lath‐shaped, length‐fast, biaxial negative (2V = 27°), with nα= 1.540, nβ= 1.612, nγ= 1.616. Li2O.2B2O3 was uniaxial negative, with ne= 1.560, nw= 1.605. Li2O.3B2O3 was biaxial negative (2V = 75° to 80°), with nα= 1.576, nβ= 1.602, nγ= 1.605. X‐ray powder diffraction data for the five crystalline compounds are presented. Thermal expansion data for Li2O‐B2O3 and Li2O.2B2O3 and limited data on the fluorescent properties of the compounds are given. X‐ray diffraction data are also presented for Li2O.B2O3.4H2O and Li2O.‐5B2O3. 10H2O. Li2O B2O3 was obtained by heating the first hydrate at 450° to 680° C. X‐ray diffraction showed Li2O.4B2O3 and Li2O‐3B2O3 to be the crystalline products obtained during heating the decahydrate at 500°C. and 600°C., respectively.

Strontium orthophosphate undergoes a rapid, reversible transition at 1305°C. The high‐temperature β form of pure Sr3false(PO4)2 cannot be quenched to room temperature, even with extremely rapid cooling. Determination of phase relationships on the orthophosphate joins between Sr3false(PO4)2 and each of the three orthophosphates, Mg3false(PO4)2 , Ca3false(PO4)2 , and Zn3false(PO4)2 showed that they form β‐ Sr3false(PO4)2 solid solutions which could be cooled to room temperature to form the basis for the so‐called “modified strontium orthophosphate” phosphors. The ranges of composition and temperature over which the β‐ Sr3false(PO4)2 solid solutions exist were determined for each system, and the existence of two ternary compounds, SrMg2false(PO4)2 and SrZn2false(PO4)2 , was confirmed. The latter compound has a transition at 1035°C, but the high‐temperature form can be maintained at room temperature only by extremetly rapid quenching. Equilibrium diagrams of each of the systems are presented to show all stability relationships.The behavior of tin‐activated β‐ Sr3false(PO4)2 solid solution phosphors in each of the three systems was explored under 2537Aå excitation, and the relation of phosphor composition to quantum efficiency, brightness, and temperature stability in the lamp‐making range was determined. The tin‐activated luminescence of the two ternary compositions was investigated using 2537Aå, 3650Aå, and cathode ray excitation.