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Home , Molybdenum trioxide

Patented May 16, 1950 gggmygaj

f’UN‘?!TIEID:v ES PATENT -- OFF HQE 2,507,691 ACID-RESISTANT ENAMELS William -.W.=',Co?een, Union, and Ralphlt. Daniel son, Elizabeth, N. J., assignors to ‘Meta! & ' ~> -»Thermit vCorporation, New~~'Yor-'k;~'>N.‘Ya a cor U poration of 1 New Jersey 'No Drawing. Application July 8,1948, Serial No. 37,518 (01.1106-49) '1 2 This invention relates to vitreous enamels for in which R0 is an selected from the class application to ferrous metals such as‘ cast , consisting of Ca; Ba, and Znoxides and which and particularly to enamels having the properties may comprise any two or all three ofthese . of acid resistance and high opacity. , One of the Alkali, metal ,oxides such as oxide K20 principal objects of the invention isto provide _ and oxide L120 may replace the enamels of the acid resistant type having im oxide in whole or in part. In general, an im proved opacity over commercial enamels of the proved opacity is favored if the F exceeds 2.5 same class, the improvement being such as to en when the vPbO exceeds 10. able the thickness of the enamel coating to be re Eachof the foregoing ingredients may be sup duced, if desired, over that ordinarily employed 10 plied from a variety of sources. For example, in without loss of quality. preparing the batch formaking the frit, sodium Broadly speaking, the invention involves an oxide may be introduced-thereto as'borax, sodium enamel or enamel frit of the -alkali metal nitrate, sodium carbonate, sodium silicate, feld borosilicate type in which b-arium-g-may or may spar, etc.; oxide as calcium’ ?uoride, not be present. ‘Within the class or type of 15 calcium carbonate, etc.; oxide as bor-ax, enamels as thus de?ned; the-invention provides either hydrated or not, boric acid, colemanite, an enamel frit having a balanced composition, razorite, etc. ; silica as ?int, feldspar, sodium resulting in-an improvement of the opacity, acid ‘silicate, etc.; dioxide as rutile, titanium resistance, and gloss, properties of the enamel. hydrate, alkali metal titanates, etc.; oxide The frit is furtherhcharacterized by the presence 20 as itself and its carbonate, etc.; lead oxide as of oxide,,usually_ calculated as the white lead, red lead, lead silicate, litharge, etc.; trioxide, as an opaci?er, and theinvention, there , ?uorine as sodium ?uoride, sodium silico ?uoride, fore, comprises a frit of balanced composition calcium ?uoride; as barium carbonate, incorporating molybdenumtrioxide as an opaci barium, nitrate, ,.barium hydroxide, ?er. 25 barium ?uoride, etc.; as it Qualitatively, the frit comprises the following self, , molybdenum sesqui oxide, and as the molybdates of zinc, barium, cal components: silica SiO2,=.,titaniaiTiO2,‘boron tri cium, lead, sodium, etc. oxide B203, alkali metal oxideRzQsuchas sodi The following examples may ‘serve to illustrate um oxide NazO, lead oxidej-PbO, ?uorine molyb the invention. denum trioxide M003, and an oxide .of ,a; metalof Example 1 group II of the periodic table, R0, selected from the class of oxides consisting of -A smelter batch composed of the following ma CaO, barium oxide B20, and ZnO. terials was made: More speci?cally, the invention comprises an Grams opaque, acid resistant enamel frit comprising es- 35 Flint ______668 sentially the following components, based on the ______, ______146 oxide or melted composition of the frit, in‘ Borax ______306 amounts de?ned by the following concentrations, Soda nitre ______'75 the latter being in terms of parts byweight: ,Soda ash ____g_____, ______159 ‘ 40 ,Sodium silico, ?uoride ______60 SiOz ______'__ 30 to 50 Zinc, oxide ______,______, ______,______24 T102 ------~- 2170 15 Calcium carbonate ______134

_ _ Litharge ______150 1 the sum of the foregoing two ingredients always Lithium carbonate ______37 being in the range of 35 to 55, 45 Zinc molybdate ______141

:BzOs ______3to 10' This batch was mixedthoroughly, smelted to a NazO ______,____, ______6 to 20 clear glass in a crucible furnace at a temperature PbO ______6to 20 of about 1950° F. for a period of approximately F ______lto 8 50 one hour, and-quenched in water. The quenched M003 ______..,2.to 8 ‘glass or frit was dried and then dry ground to R0 ______.., 4~to 15 a ?neness such :that about, 95%.passed a 100 mesh 2,507,691 3 4 screen. The frit had substantially the following also be applied, in appropriate cases, by the wet oxide composition in terms of parts by weight: process by wet milling the frits with the usual mill additions to form enamel slips and applying S102 ______._ 43.7 the slips by spraying or dipping. Conventional T102 ______._ 9.2 temperatures and times of application for the B203 ______._ 7.1 wet or dry process may be employed. R20: In the light of the foregoing description, the NazO ______11.9 following is claimed: L120 ______._ 1.0 1. An opaque, acid resistant enamel frit con PbO ______9.5 sisting essentially of the following components, F ______2.3 based on the melted composition of the frit, in M003 ______._ 5.7 amounts de?ned by the following concentrations, R0: the latter being in terms of parts by weight: ZnO ______4.8 5102 ______30 to 50 02.0 ______4.8 15 T102 ______2 to 15 A cast iron sample plate was cleaned by sand blasting and sprayed with an ordinary dry the sum of the foregoing two ingredients always process ground coat enamel or “slush” coat. The being in the range of 35 to 55, slush coat was dried, the plate weighed and then B203 ______3 to 10 placed in a gas-?red muffle furnace at 1600° F. u R20 ______6 to 20I for 8 minutes to allow the iron to be thoroughly in which R20 is an alkali metal oxide selected heated. The plate was removed and placed on from the class consisting of Na, K, and Li oxides, one pan of a balance and the enamel powder dusted on the plate evenly through a vibrating PbOl ______6 to 20 screen until 30 gms. (corresponding to a coating 25 F ______1 to 8 of 180 gms. per sq. ft.) had been applied. The the F exceeding 2.5 when the PhD exceeds 10. plate was then returned to the furnace for a period of 1 minute, removed, and the dusting re Moon ______2 to 8 peated, making a total thickness of coating of R0 ______4 to 15 360 gms. per sq. ft. The plate was then ?red for 30 in which R0 is an oxide selected from the class 1 minute and allowed to cool. The acid resist consisting of 0210, BaO, and ZnO. ance and opacity of this enamel were measured 2. An opaque, acid resistant enamel frit con and compared with that of a commercial enamel sisting essentially of the following components, employing sodium antimonate, a standard opaci based on the melted composition of the frit, in ?er. The latter enamel was applied to an iden 35 amounts de?ned by the following concentrations, tical plate in the manner just described. The the latter being in terms of parts by weight: following results were obtained: S102 ______30 to 50 TiOz ______2 to 15 Re?ectance the sum of the foregoing two ingredients always 40 being in the range of 35 to 55, Blue Green Amber B203 ______3 to 10 NazO ______6 to 20 Example 1 ______S2 85 85 Commercial ______79 82 82 PbO ______6 to 20 F ______1 to 8 Both of the foregoing enamels had grade AA acid the F exceedings 2.5 when the PhD exceeds 10, resistance. Other enamel frits prepared according to the M002. ______{2 to 8 R0 ______4 to 15 invention are as follows: in which R0 is an oxide selected from the class consisting of CaO, BaO', and ZnO. Example No... 2 3 4 5 6 7 8 9 3. An acid resistant enamel frit having sub stantially the following composition, all amounts S107 ______43. 8 44. 2 40. 3 47. 4 43. 5 36.1 47. 3 47. 3 T107 ______9. 2 9.3 5.4 5.4 9.3 9. 9 5. 8 5.8 being in terms of parts by weight: gag; ______7.1 7.2 9.9 7.2 7.2 5.9 7. 7 7.7 2 : S102 _-_.‘ ______43.7 azO______12. 9 12.0 12.7 12.9 12.9 13.5 9. 8 14.0 T102 ______9.2 Li20______-_ 1. O . _ _ . ______9. 5 9. 6 15. l 9. 5 9. 5 19.1 10. 3 6. 1 B203 ______7.1 2.3 2.3 2.9 2.3 2.3 3.8 2.5 2.5 5.7 4.8 5.7 5.7 5.7 5.6 6.2 6.2 NazO ______11.9 L120‘ ______1.0 2.8 4.8 1.9 4.8 4.8 1.0 5.2 5.2 6.7 4.8 6.1 4.8 4.8 5.1 5.2 5.2 60 PbO ______9.5 ance ______- AA AA AA A AA A AA A FM003 ______5.7 Reflectance (green) ______85 82 82 87 85 78 82 84 ZnO ______4.8 CaO ______4.8 The acid resistance tests were carried out ac 65 WILLIAM W. COFFEEN. cording to the procedure described in “Test for RALPH R. DANIELSON. Acid Resistance of Porcelain Enamels," Part I— Flatware, pages 4-6, April, 1940, Porcelain Enamel REFERENCES CITED Institute, Inc. The re?ectance data were ob The following references are of record in the tained with a standard Hunter multi-purpose ?le of this patent: re?ectometer according to the standard re?ect UNITED STATES PATENTS ance test of the Porcelain Standards Section, Porcelain Enamel Institute, Inc., revised August, Number Name Date 1944. While the enamel frits in the above exam 2,245,541 Goodwin ______June 10, 1941 ples were applied by the dry process, they may 75 2,294,760 Morris ______Sept. 1, 1942