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Low thermal conductivity low density pyrolytic boron nitride material, method of making, and articles made therefrom

A thermal conductivity, boron nitride technology, used in chemical instruments and methods, polycrystalline material growth, metal material coating process, etc., can solve problems such as limiting thermal gradients, and achieve high thermal control and high anti-shedding effect.

Inactive Publication Date: 2011-01-19
MOMENTIVE PERFORMANCE MATERIALS INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This anisotropy facilitates a highly uniform temperature profile in the molten semiconducting material within the crucible, but it limits the control of thermal gradients that may be required for optimal crystal production

Method used

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  • Low thermal conductivity low density pyrolytic boron nitride material, method of making, and articles made therefrom
  • Low thermal conductivity low density pyrolytic boron nitride material, method of making, and articles made therefrom
  • Low thermal conductivity low density pyrolytic boron nitride material, method of making, and articles made therefrom

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Eight standard density p-BN samples and 11 ultra-low density (ULD) p-BN samples produced according to the method described here were tested for density using a helium pycnometer. Samples were obtained by cutting small pieces of p-BN from a VGF crucible deposited on a graphite mandrel under the conditions described below. ULD p-BN was provided under the following reaction conditions: a temperature of 1750 °C, a pressure of 0.35 Torr, 2.4 liters per minute of BCl 3 Flow rates, ammonia flow rate of 6.5 liters per minute and nitrogen flow rate of 0.50 liters per minute.

[0030] Table 2

[0031] (Comparison of the density of standard density p-BN and ULD p-BN)

[0032]

[0033] variance

Embodiment 2

[0035] The thermal diffusivity and heat capacity of 8 samples of standard density conventional p-BN, layered p-BN and ULD p-BN of the present invention were measured. Samples were produced by CVD and cut from the top of the crucible. Layered p-BN is produced by pulsing dopant gases. Layered p-BN has higher density and different material properties (TC, mechanical strength, crystallinity, and orientation). Layering reduces shedding resistance. Measurements were performed by laser flash, diffusion coefficient and hot disc methods. The thermal conductivity is calculated according to the following formula.

[0036] α = k ρ · c p

[0037] in:

[0038] α is the thermal diffusivity,

[0039] k is the thermal conductivity,

[0040] ρ is the density, and

[0041] C p is the heat capacity

[0042] now refer to figure 2 , showing the through-surface...

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Abstract

A pyrolytic boron nitride material is disclosed having an in-plane thermal conductivity of no more than about 30 W / m-K and a through-plane thermal conductivity of no more than about 2 W / m-K. The density is less than 1.85 g / cc.

Description

technical field [0001] The present invention relates to pyrolytic boron nitride materials, methods of making said materials, and articles made therefrom. Background technique [0002] Boron nitride (BN) is typically shaped into manufactured articles. Boron nitride (BN) is a well known commercially produced refractory non-oxide ceramic material. Pyrolytic boron nitride (p-BN) can be fabricated on substrates such as graphite by chemical vapor deposition (CVD). The most common structure of BN is the hexagonal structure. The structure is similar to the carbon structure of graphite, which consists of edge-fused six-membered (BN) 3 The extension of the ring consists of two-dimensional layers. The rings are arranged in such a crystal form that B atoms on a ring in one layer are above and below N atoms in an adjacent layer, and vice versa (ie, the rings vary in position relative to the layer). Similar to graphite, the in-plane B-N bonds in the fused six-membered rings are stron...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B41/50C23C16/34
CPCC30B25/00C30B35/002C23C16/01C30B29/403C30B11/002C23C16/342Y10T428/131
Inventor 马可·沙普肯斯狄米特律斯·萨利贾尼斯道格拉斯·朗沃斯
Owner MOMENTIVE PERFORMANCE MATERIALS INC
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