Carborundum fireclay is used at blast furnace carborundum to set a brick. Do brick of leg of extinguish anxious ox. Bricky build by laying bricks or stones builds silica brick of aluminous electrobath carbonization and carborundum of kiln of pottery and porcelain or felt. At present carborundum slop basically is given priority to with carborundum grain and fine pink want raw material, it is bond with colophony of liquid phenolic aldehyde, maintain strength tall. Stability of structure of system of build by laying bricks or stones and air-tightness are good. The advantage of stable physics and chemical function. A few manufacturer use carborundum to abandon a brick to make nitrogen change silicon and carbonization silica brick, the user also hopes the chemical composition of fireclay and brick are similar. However, nitrogen changes silicon to oxidize more easily than carborundum, whether does function satisfy the slop that because this contains nitrogen,changes silicon to use need test and verify for a long time. Carborundum is used at this job. Nitrogen changes silicon and nitrogen to change silicon to combine carborundum to abandon bricky pink is the main raw material that nitrogen turns silicon to combine carborundum brick. . Contrast studied bonding strength is mixed fight oxidisability.
1. experiments (1) raw material and deserve to be than main raw material: Granuality 0.5 ～ 0mm and ≤ 0.074mm. ω (SiC)= carborundum granuality 98.31% ≤ 0.074mm. ω (Si3N4)= nitrogen changes silicon to be 93.26%.5 ～ 0mm and ≤ 0.074mm. ω (SiC)=74.42% . ω (Si3N4)=20.26% nitrogen changes silicon and carborundum to abandon bricky pink union, choose liquid phenolic aldehyde colophony and a few additive. If sample composition expresses 1 to show. Mark of sample of carborundum raw material is A, compound nitrogen changes carborundum B of mark of sample of silicon raw material, carborundum combines carborundum to abandon C of mark of sample of bricky pink raw material.
(2) sample preparation and function test pour ready data into mixer, dry mix 1min, join colophony of liquid phenolic aldehyde next wet mix 66min, make slop, initiative awl is entered degree it is evaluation standard to decide bond adds a capacity about for 450mm, bond of 3 groups of sample joins a quantity to be mixed for 26%.31% respectively 33% . Next according to. GB/T consistency (awl enters degree of law) and fight lose bonding strength (11008 ℃ and 24h of 180 ℃ drying, ℃ of 600 ℃ .800 and atmosphere of 1300 ℃ air and the heat treatment 3h below the condition that bury charcoal) , make cubic test block of 50mm of × of 50mm × 50mm fight oxidation function to check (600 ℃ and) of atmosphere of 800 ℃ air.
2 results and discuss (1) raw material enters spent influence to be in temperature to slop awl (25 ± 5) ℃ , humidity falls for the condition of 20%~25% , it is the condition of 20%~25% according to humidity, GB/T22459.1-2008 undertakes to 3 groups of sample awl enters degree of test, the awl of different time is entered if the graph is shown 1 times,spend. Can see, 3 groups of mud are entered by awl of 450mm agitate left and right sides after spending, as the elapse of time, awl is entered degree produced very big change. Compound nitrogen changes synthetic carborundum raw material and carborundum AB of silicon raw material the elapse as time, the awl of sample is entered degree appear first big hind small metabolic current. But degree of value is entered to maintain in 5h awl in 435mm afore-mentioned material have longer construction time. The analysis thinks to there is the water of certain amount in phenolic aldehyde colophony. Alcohol and volatile material, initiative moisture and carborundum raw material are completely not wet, the elapse as time gradually wet raw material, material taper increases; In addition, moisture. The volatilization of alcohol and volatile material can increase the viscosity of slop, bring about awl to enter degree reduce. Enter degree of change trend that presents basically to be reduced gradually in order to abandon the C sample awl that bricky pink is main raw material, because the brick is using the infiltration in the process,the likelihood is a few basic material, after mixing, dissolve gradually, bring about solidify of phenolic aldehyde colophony, reduce slop awl to enter thereby degree.
Awl of sample of fireclay of different raw material is entered degree along with time change graph 1 (2) raw material fights the influence felt sample that loses bonding strength to be in to slop different temperature has heat treatment below amiable atmosphere, after heat treatment fight if the graph is shown 2 times,break result of bonding strength test.
Graph 2 raw material fight the change that loses bonding strength to pursue after the heat treatment in air atmosphere 2 it is thus clear that 3 groups of sample are in after 110 ℃ are dry fight fold bonding strength difference bigger, among them the bonding strength of appearance of A of complete carborundum raw material exceeds 25MPa, carborundum and nitrogen change the B sample intensity of silicon raw material to be close to 25MPa, be not worth 20MPa in order to abandon the C sample intensity that bricky pink is main raw material. Difference of the intensity after 180 ℃ are dry is not big, all be 22MPa left and right sides. The analysis thinks, of microtherm slop fight fold bonding strength to basically be offerred by phenolic aldehyde colophony, because of these 3 groups of sample fight lose strength opposite taller. From the graph 2 in also can see, the strength of 3 groups of sample is relative below 3 temperature inferior, as heat treatment temperature elevatory, the sample A intensity that is raw material with pure carborundum is higher, the intensity difference of B sample and C sample is not big. The analysis thinks, phenolic aldehyde colophony is in in oxidize gradually in air below high temperature condition decompose, produce the effect of binder no longer, systematic intensity basically is offerred by the agglomeration between raw material, nitrogen changes silicon to oxidize more easily than carborundum, a few oxidation silicon diaphragm can raise sample normal temperature to fight lose strength, but a large number of oxidation can bring about a structure inattentive, reduce intensity. Temperature and atmosphere differ after heat treatment fight fold bonding strength to if the graph is shown 3 times,contrast.
Graph the influence of 50% discount bonding strength sees requirement of 3 different heat treatment, 3 groups of sample are in what temperature of 3 kinds of heat treatment falls to fight lose bonding strength summary prep above buries charcoal sample, especially when 13000 ℃ heat treatment, its are fought fold bonding strength to was not worth 5MPa to lift 10MPa above, a type intensity exceeds 14MPa. Below condition of all heat treatment, of A sample fight lose bonding strength taller, the likelihood is the agglutinate dose that requires as a result of place of A sample slop relatively lesser, the hole that after volatile mark volatilizes, leaves is less, b of sample of excel of effect of agglomeration of the sample in heat treatment process and sample C. (3) the wear that raw material fights the influence of oxidation function to change silicon and photograph of carborundum brick slop to be united in wedlock to study nitrogen of different raw material to slop, sample of 3 groups of fireproof slop 800 ℃ undertake below the condition function compares an experiment fighting oxidation, photograph of section plane of the sample after oxidation is shown 4 times like the graph.
Graph 4800 ℃ fight photograph of oxidation sample section plane to see, 3 groups of sample after 8000 ℃ oxidize, the photograph is in an oxidation layer appears all round sample, oxidation layer ply is thicker, the difference of oxidation layer ply of A sample and C sample is not big, of A sample fight oxidation function opposite better. When the analysis thinks 8000 ℃ change silicon to oxidize more easily than carborundum when nitrogen, nitrogen changes silicon / the glair layer that stability cannot form in sample surface after carborundum oxidizes, the B sample oxidation that because of this nitrogen the raw material that change silicon introduces is more serious, c is in sample, nitrogen turns raw material of silicon consist in in, its fight oxidation function slightly good at B sample, still be inferior to be the A sample of raw material with pure carborundum.
3. conclusion (1) the binder that carborundum silicon needs for the sample place of raw material is less, the binder that needs in order to abandon the sample that bricky pink is raw material is more. Enter degree of elapse as time in order to synthesize raw material for the awl of two kinds of slop of main raw material and reduce, enter degree of elapse as time in order to abandon bricky pink for the awl of the slop of raw material and reduce, not stable. (2) after low temperature of 3 groups of sample is dry fight lose bonding strength taller, the sample intensity after 180 ℃ are dry is basic and same, make an appointment with 22MPa. But in the intensity after high temperature heat treatment is inferior, below air atmosphere 600 ℃ and intensity of the sample after 800 ℃ heat treatment are not worth 5MPa. After next heat treatment, sample intensity increases significantly. 13000. After ℃ buries charcoal heat treatment, sample intensity all exceeds 10MPa. (3) the sample that is raw material with pure carborundum is had fight oxidation function goodly, in be being had in order to abandon bricky pink for the sample of raw material, wait fight oxidation function, nitrogen changes sample of silicon raw material fight oxidation function opposite poorer.
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