Beta'-Sialon whisker gas phase reaction preparation method

Abstract

The invention discloses beta'-Sialon whisker gas phase reaction preparing method, which comprises the following steps: adopting grammite, bauxite and carbon black as raw material; ball-grinding; screening; batching; wet-blending; drying; dry-blending; proceeding high-temperature gas phase synthesis; blowing flow nitrogen into furnace continually; reacting at 1400-1450 deg.c for 4-10 h; heating and cooling at 3-5 deg.c per min; preparing beta'-Sialon whisker through gas phase reaction of SiO gas, Al2O gas, CO gas and nitrogen in the reducing process. The invention possesses entire crystal structure, high strength, high modulus and good chemical stability with 1-10mm whisker length, 20-50 mum diameter, which displays good reinforced toughening action for Sialon ceramics and other ceramic material.

Description

technical field

[0001] The invention relates to the technical field of ceramic materials, in particular to a gas phase reaction preparation method for β'-Sialon whiskers. Background technique

[0002] Sialon ceramics are considered to be one of the most promising high-temperature structural ceramics due to their excellent mechanical properties, thermophysical properties and chemical stability, and have broad application prospects in metallurgy, aerospace, transportation, chemical machinery, building materials, medicine and other fields . Sialon ceramics are mostly prepared from pure nitrides and oxides by reaction sintering or natural aluminosilicate minerals are prepared by carbothermal reduction nitriding method, but the materials prepared by the above methods are all bulk Sialon ceramics or Sialon powder . Sialon ceramics, like other ceramic materials, have an Achilles' heel in brittleness. Once a crack is generated, it is easy to expand and cause catastrophic fracture....

Examples

Embodiment 1

[0026] The process steps are as follows:

[0027] (1) Ball milling: finely grind the raw materials until the particle size of the raw materials reaches below 74 μm;

[0028] (2) Sieving: in order to ensure the average particle size and particle size distribution of the powder, use a 74 μm standard sieve to sieve the raw material powder with a relatively dispersed particle size;

[0029] (3) Batching: 26.85wt% by silica fume, 47.39wt% bauxite, and 25.76wt% carbon black;

[0030] (4) Wet mixing: The prepared mixture is ball milled and mixed with absolute ethanol as the medium, and the wet mixing time is 18 hours:

[0031] (5) Drying: put the wet-mixed slurry into an oven and dry at 80°C;

[0032] (6) Dry mixing: the mixture is fully dried and then ball milled and dry mixed for 6 hours to ensure that the mixture is fully uniform;

[0033] (7) High-temperature gas-phase synthesis: put the mixture into a porous graphite crucible and place it in a vertical MoSi 2 High temperatur...

Embodiment 2

[0036] The process steps are as follows:

[0037] (1) Ball milling: finely grind the raw materials until the particle size of the raw materials reaches below 74 μm;

[0038] (2) Sieving: in order to ensure the average particle size and particle size distribution of the powder, use a 74 μm standard sieve to sieve the raw material powder with a relatively dispersed particle size;

[0039] (3) Batching: 52.64wt% of silica fume, 23.21wt% of bauxite, and 24.15wt% of carbon black;

[0040] (4) Wet mixing: place the prepared mixture in a polyurethane ball mill tank, and use absolute ethanol as a medium for ball milling and mixing, and the wet mixing time is 24 hours;

[0041] (5) Drying: put the wet mixed slurry into an oven and dry at 60°C;

[0042] (6) Dry mixing: the mixture is fully dried and then ball milled and dry mixed for 4 hours to ensure that the mixture is fully uniform;

[0043] (7) High-temperature gas-phase synthesis: put the mixture into a porous graphite crucible ...

Embodiment 3

[0046] The process steps are as follows:

[0047] (1) Ball milling: finely grind the raw materials until the particle size of the raw materials reaches below 74 μm;

[0048] (2) Sieving: in order to ensure the average particle size and particle size distribution of the powder, use a 74 μm standard sieve to sieve the raw material powder with a relatively dispersed particle size;

[0049] (3) Batching: 47.78wt% by silica fume, 21.07wt% bauxite, and 31.15wt% carbon black;

[0050] (4) Wet mixing: the prepared mixture is ball milled and mixed with absolute ethanol as the medium, and the wet mixing time is 20 hours;

[0051] (5) Drying: put the wet mixed slurry into an oven and dry at 70°C;

[0052] (6) Dry mixing: the mixture is fully dried and then ball milled and dry mixed for 5 hours to ensure that the mixture is fully uniform;

[0053] (7) High-temperature gas-phase synthesis: put the mixture into a porous graphite crucible and place it in a vertical MoSi 2 High temperature ...

technical field

[0001] The invention relates to the technical field of ceramic materials, in particular to a gas phase reaction preparation method for β'-Sialon whiskers. Background technique

[0002] Sialon ceramics are considered to be one of the most promising high-temperature structural ceramics due to their excellent mechanical properties, thermophysical properties and chemical stability, and have broad application prospects in metallurgy, aerospace, transportation, chemical machinery, building materials, medicine and other fields . Sialon ceramics are mostly prepared from pure nitrides and oxides by reaction sintering or natural aluminosilicate minerals are prepared by carbothermal reduction nitriding method, but the materials prepared by the above methods are all bulk Sialon ceramics or Sialon powder . Sialon ceramics, like other ceramic materials, have an Achilles' heel in brittleness. Once a crack is generated, it is easy to expand and cause catastrophic fracture....

Examples

Embodiment 1

[0026] The process steps are as follows:

[0027] (1) Ball milling: finely grind the raw materials until the particle size of the raw materials reaches below 74 μm;

[0028] (2) Sieving: in order to ensure the average particle size and particle size distribution of the powder, use a 74 μm standard sieve to sieve the raw material powder with a relatively dispersed particle size;

[0029] (3) Batching: 26.85wt% by silica fume, 47.39wt% bauxite, and 25.76wt% carbon black;

[0030] (4) Wet mixing: The prepared mixture is ball milled and mixed with absolute ethanol as the medium, and the wet mixing time is 18 hours:

[0031] (5) Drying: put the wet-mixed slurry into an oven and dry at 80°C;

[0032] (6) Dry mixing: the mixture is fully dried and then ball milled and dry mixed for 6 hours to ensure that the mixture is fully uniform;

[0033] (7) High-temperature gas-phase synthesis: put the mixture into a porous graphite crucible and place it in a vertical MoSi 2 High temperatur...

Embodiment 2

[0036] The process steps are as follows:

[0037] (1) Ball milling: finely grind the raw materials until the particle size of the raw materials reaches below 74 μm;

[0038] (2) Sieving: in order to ensure the average particle size and particle size distribution of the powder, use a 74 μm standard sieve to sieve the raw material powder with a relatively dispersed particle size;

[0039] (3) Batching: 52.64wt% of silica fume, 23.21wt% of bauxite, and 24.15wt% of carbon black;

[0040] (4) Wet mixing: place the prepared mixture in a polyurethane ball mill tank, and use absolute ethanol as a medium for ball milling and mixing, and the wet mixing time is 24 hours;

[0041] (5) Drying: put the wet mixed slurry into an oven and dry at 60°C;

[0042] (6) Dry mixing: the mixture is fully dried and then ball milled and dry mixed for 4 hours to ensure that the mixture is fully uniform;

[0043] (7) High-temperature gas-phase synthesis: put the mixture into a porous graphite crucible ...

Embodiment 3

[0046] The process steps are as follows:

[0047] (1) Ball milling: finely grind the raw materials until the particle size of the raw materials reaches below 74 μm;

[0048] (2) Sieving: in order to ensure the average particle size and particle size distribution of the powder, use a 74 μm standard sieve to sieve the raw material powder with a relatively dispersed particle size;

[0049] (3) Batching: 47.78wt% by silica fume, 21.07wt% bauxite, and 31.15wt% carbon black;

[0050] (4) Wet mixing: the prepared mixture is ball milled and mixed with absolute ethanol as the medium, and the wet mixing time is 20 hours;

[0051] (5) Drying: put the wet mixed slurry into an oven and dry at 70°C;

[0052] (6) Dry mixing: the mixture is fully dried and then ball milled and dry mixed for 5 hours to ensure that the mixture is fully uniform;

[0053] (7) High-temperature gas-phase synthesis: put the mixture into a porous graphite crucible and place it in a vertical MoSi 2 High temperature ...

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