The charge for making adravastoi corundum ceramics
(57) Abstract:The invention consists in that upon receipt of the charge alumina brand G-00 mixed with natural refractory bauxite following composition, wt.%: Al2O3- 69,4; SiO2- 8,18; TiO2- 3,42; Fe2O3is 2.55; MgO - 1,10; Na2O - 0,26; K2O - 0,54; P2O5- 0,54; V2O5- 0,40; SPT - 13,61 when the mass ratio of alumina and bauxite to 3.5:1. Received corundum ceramics has a higher stress intensity factor and can be used in the manufacture of parts operating under high shock loads. table 1. The invention relates to the production of ceramic materials, namely, to obtain corundum ceramics with high stress intensity factor and service life under shock loads, and can be used in the manufacture of ceramic components, working in conditions of severe vibration, high-impact shock-explosive character.The known composition of the charge corundum ceramics fracture toughness of from 3.5 to 4.0 MPa m-1/2and tensile strength Flexural 280 300 MPa  For the manufacture of material>30,48. Supplements of chromium, silicon, manganese optimal form dense microstructure of the material providing a sufficient mechanical strength of the material.The disadvantage of this method of obtaining corundum ceramics is the high consumption of high-purity reagents and not enough high strength characteristics, reducing the operational readiness of the ceramic material.The purpose of the invention to provide a composition of the mixture for the manufacture of corundum ceramics with a high critical stress intensity factor while maintaining the strength of ceramics bending at the level of the most widely used corundum ceramics type VK-94-1  and reduced consumption of high-purity reagents.The invention consists in that in the preparation of the charge alumina brand G-00 mixed with complex natural supplements refractory bauxite following composition, wt. Al2O369,4; SiO28,18; TiO23,42; Fe2O32,55; MgO 1,10; Na2O - 0,26; K2O 0,54; P2O50,40; SPT 13,61 when the ratio of alumina and bauxite of 3.5:1 (chemical analysis of bauxite are made with precision to 2 mass.).During the heat treatment is formed dense MIC. optimalnoe the combination of these phases increases the elastic and strength properties of ceramics.The method is as follows.Alumina brand G-00 mixed with complex natural mineral additive white bauxites of the following composition, wt. Al2O3- 69,4; SiO28,18; TiO23,42; Fe2O32,55; MgO 1,10; Na2O 0,26; K2O 0,54; P2O20,54; V2O50,40; SPT 13,61. The ratio of alumina bauxite in charge of the mixture is 3.5:1. The mixture after grinding sifted in the sieve 063. As the ligament using 5% solution of carboxymethylcellulose. From the obtained mixture with a force of 35 to 50 MPa extruded balocchi size 8 x 8 x 85. After drying the samples in air produced the firing at a temperature of 1550 - 1600oC.Determination of mechanical properties of ceramics produced in the following way. Bending strength was determined by three-point scheme with a bursting machine PH-500. The critical stress intensity factor was determined by the method of calculating the propagation of cracks after pressing identia. As test pieces were used balocchi with a machined surface (see table). The charge for production at the I same time, as the oxide supplements used natural refractory bauxite following composition, wt.Al2O369,4
moreover, alumina and bauxite is mixed in a ratio of 3.5 to 1 wt.h.
FIELD: refractory industry, in particular corundum parts for ferrous and non-ferrous metallurgy.
SUBSTANCE: on the step of batch preparation surface of fused corundum filler spheroid particles is damped with oleic or stearic acid in amount of 0.5-0.0 mass % in respect to total mass of phosphate binder. During agitation fine dispersed intergrinding mixture containing (mass %): Al2O3 47-80, ZrO2-SiO2 20-53, and phosphate binder (e.g. phosphoric acid or aluminum phosphate) is added. Batch contains (mass %): fused corundum filler 50-70; fine dispersed intergrinding mixture 30-50; phosphate binder over 100 % 5-10. Batch is homogenized, formed, solidified in air, baked at decomposition temperature of zircon concentrate, and cooled with isothermal holding at 1100-9000C.
EFFECT: corundum-based articles with improved strength and heat resistance.
7 cl, 2 tbl