| Name | Aluminum borate |
| Synonyms | AlBO2 Aluminum borate alumanyloxy(oxo)borane Aluminum borate whisker |
| CAS | 61279-70-7 |
| InChI | InChI=1/Al.BHO2.2H/c;2-1-3;;/h;2H;;/rAlH2.BHO2/c;2-1-3/h1H2;2H |
| Molecular Formula | H3AlBO2 |
| Molar Mass | 72.8152 |
| Physical and Chemical Properties | A single crystal with extremely fine chemical properties. The general formula is, nAl2O3?m B2O3. Usually 9A12O3?2B2O3, 2 Al2O3?B2O3, A12O3?B2O3 three forms of compounds exist in natural minerals. The industrial whisker is 9 Al2O3?2B2O3. Relative density 2.93. Melting point 1440 ℃. The heat-resistant temperature is 1200 ℃. Mohs hardness 7. The chemical properties are basically neutral. It has high elastic modulus, good mechanical strength, heat resistance, chemical resistance, acid resistance (stable at 70°C in 1 mol/L hydrochloric acid), electrical insulation and neutron absorption properties. Aluminum borate whiskers have higher elasticity and strength than potassium titanate whiskers. Elastic modulus 392000 Mpa and tensile strength 7840 Mpa. |
| Use | Applications can be used as a reinforcing material for plastics, metals, ceramics, etc. When used as a plastic reinforcing agent, compared with the glass fiber, the small, complex shape of the plastic molding can play a reinforcing role. Directionality is given to products, etc. It can also be used as a reinforcing material for polycarbonate resin. |
nature:
1. Aluminum borate is a colorless crystal or white powder, odorless and tasteless.
2. Aluminum borate is stable in air and almost insoluble in water, but soluble in concentrated nitric acid.
Usage:
1. As an additive in ceramic materials, it provides thermal and chemical stability.
2. Used as a raw material for glass ceramic materials.
3. Used as a raw material for thermal barrier coatings.
4. Used for preparing high-temperature refractory materials, etc.
Method:
Aluminum borate can be prepared by reacting boric acid and aluminum hydroxide: H3BO3+Al (OH) 3 → H3AlBO3+3H2O
Security information:
1. Aluminum borate itself has minimal impact on the human body and environment, but inhalation of dust or contact with the skin should be avoided.
2. Suitable protective equipment should be worn during preparation or use to ensure good ventilation.
3. Avoid contact with strong oxidants to prevent the generation of harmful gases.
4. During storage and handling, attention should be paid to avoiding mixing or contact with other chemicals.
The melting method mixes alumina with boric acid or boron oxide, melts at 2100°C, then cools to grow into whiskers.
This method can only grow whiskers over tens of microns.
In the gas phase method, water vapor is passed into aluminum fluoride and boron oxide in the gas state at 1000~1400 ℃ to obtain aluminum borate whiskers. This method is not easy to operate.
The internal melting method reacts alumina, or a compound that generates alumina at high temperature, with boron oxide at 1200~1400 ℃, and boron oxide acts as a flux at the same time, and finally aluminum borate whiskers are obtained.
This method can only obtain large-size whiskers. At the same time, because boron oxide acts as a flux, the whisker is dissolved and the yield is reduced.
The external melting method is above 1000 ℃, adding flux unrelated to the reaction (such as alkali metal chloride, sulfate or carbonate) into alumina and the raw materials that produce boron oxide, and growing into whiskers at 1000~1200 ℃. After the reaction, water treatment is used to remove the flux and separate the whiskers. When the reaction temperature is 800~1000 ℃, 2A12O3?B2O3 whisker.
This method has lower reaction temperature, lower energy consumption and higher yield than the melting method and gas phase method. This method is generally used in industry.
Using trialkali aluminum sulfate [M3 AI(S04)3](M is alkali metal) and boron oxide, oxyacid or alkali metal borate as raw materials, the molar ratio of aluminum to boron is 6:4~9:2, the mixture is reacted at 700~1200 ℃ to obtain aluminum borate whiskers.