JPS6018249A - High emissivity investment casting mold for casting super alloy by unidirectional solidification - Google Patents

Abstract

PURPOSE:To improve the heat radiation of a casting mold and to accelerate the unidirectional solidification of a super alloy by coating the powder of the lower oxide of titanium, more preferably the lower oxide of titanium which is blackened and has high emissivity on the outside layer part of a shell mold for casting. CONSTITUTION:Titanium is heated to about >=1,000 deg.C in a reducing atmosphere to release oxygen in TiO2 and to change the same to lower oxide, thereby yielding blackened TiO1.75-TiO1.65. The above-mentioned lower oxide is then coated on the outside layer of a casting mold with a binder consisting of butyl titanate and is calcined at a high temp. to complete an investment casting mold having the outside layer of high emissivity. The conversion to the lower oxide of titania can be accomplished in the process of manufacturing the casting mold as well. The heat radiatability of the titled casting mold is thus improved and the temp. gradient of the solid-liquid boundary during unidirectional solidification of the super alloy is increased and the crystal growth in the prior bearing direction of the alloy is accelerated.

Description

【発明の詳細な説明】 チクニア（“Ｊ’、ｉ、０２）は還元雰囲気■３．１０
００°Ｃ以上で加熱すると次第にＪ’ｉ０２中の酸素が
放出され、チクニアの低次酸化物に変化するとともに、
チタニア白痢、次第に黒色化し放Ｉ、１率も開化する。[Detailed description of the invention] Chikunia (“J', i, 02) is a reducing atmosphere ■3.10
When heated above 00°C, oxygen in J'i02 is gradually released and changes to lower oxides of chiknia,
Titania dysentery gradually turns black and becomes open to the public.

チタニアの酸化度と色調および放Ｊ＆＝１率の開化を次
の表に示した。The oxidation degree, color tone, and release rate of titania are shown in the following table.

このように、チタニアは低次酸化物に移行するとともに
色調が変化し、当然のととく放射率も変化して、黒色化
した’ｒｉｏ、、ｙ、、〜Ｔｉ−０．，６５のものは高
放射率となる。ちなみに１．！；　００　’Ｃにおいて
測定した’ＩＪ−０，，と’Ｉ’　５−０．、、５〜Ｔ
１０１，６５に入る低次酸化物を比較してみると約３倍
近くの差があり、’ｎｏ２の低次酸化物は高放射率とな
ることが明らかである。In this way, as titania transitions to a lower oxide, its color tone changes, and of course its emissivity also changes, resulting in a blackened 'rio,,y,,~Ti-0. , 65 has a high emissivity. By the way, 1. ! 'IJ-0,, measured at 00'C, and 'I' 5-0. ,,5~T
Comparing the lower oxides of No. 101 and 65, there is a difference of nearly three times, and it is clear that the low-order oxide of No. 2 has a high emissivity.

このように、高放射率を有するチタニアの低次酸化物を
インベストメントシエ／ｌ／タテ型の外層Ｋｆｌ促進さ
れる。In this way, a low-order oxide of titania having a high emissivity is promoted as an investment layer/l/vertical type outer layer Kfl.

次に、実施例により、本発明の詳細な説明すτ。Next, the present invention will be explained in detail by way of examples.

実施例／ 実施例／では、黒色化したチタニアの低次酸化物をブチ
ルチタネートの結合材により塗布し、外層を形成する。Example/ In Example/, a blackened lower oxide of titania is applied with a binder of butyl titanate to form an outer layer.

ブチルチタネートは高温焼成にょｐＴｉ０２から次第に
ＴｉＯ２−尤の形となり、添加したチタニアの低次酸化
物とともに高放射率の外層を有スるインイヌ１−メント
鋳型となる。The butyl titanate gradually changes from the high-temperature fired pTi02 to the TiO2-like form, and together with the added lower oxide of titania, becomes an in-product mold having a high emissivity outer layer.

実施例２ 実施例２で得られたインベストメン１−鋳型の焼成前は
白色の外層を有した鋳型であるが、とのシエ）Ｖ鋳型を
還元雰囲気中、７２００°Ｃで７時間焼成することによ
り外層の’Ｌ’ｉ０２から次第に酸素が抜けて低次酸化
物に変化するとともに外層は黒色化し、高放射率を有す
るインベヌトメント鋳型となる。Example 2 The Investmen 1-Mold obtained in Example 2 is a mold with a white outer layer before firing. As a result, oxygen gradually escapes from 'L'i02 in the outer layer and changes to a lower-order oxide, and the outer layer turns black, resulting in an inventive mold having a high emissivity.

【図面の簡単な説明】[Brief explanation of drawings]

第１図には、実施例／で？１）られた高放射率インベヌ
トメント鋳型を示す。 第３図には、実施例−により高放射率インベヌトメント
鋳型が得られる過程を示す。FIG. 1 shows an example/in? 1) Shows the high emissivity inventive mold. FIG. 3 shows the process of obtaining a high emissivity injection mold according to the example.

Claims (2)

【特許請求の範囲】[Claims] （１）チクニア（’］’１０２）の低次酸化物、好まし
くは黒〔５化したＵ’ｊ−０，，７５〜Ｔ：ＬＯ，，６
５の粉末をシェル層の外層部に被覆した高放創串インベ
ストメント鋳型。(1) Lower oxide of chikunia (']'102), preferably black [5-ized U'j-0,,75~T:LO,,6
A high-radiation skewer investment mold in which the outer layer of the shell layer is coated with powder No. 5. （２）　シエ／ｌ／鋳型の製作過程において、外層部に
チクニア（’Ｉ’ｉ０□）を被覆し、この鋳型を還元雰
囲気中高温、好ましくは１０００°Ｃ以上に加熱して、
チタニアの被覆層を７項に記したような黒色化したチク
ニアの低次酸化物（Ｔｉ−ｏ２−χ）とした高放射率イ
ンベラ１ノントＶｆ型。(2) In the process of manufacturing the shell/l/mold, the outer layer is coated with chikunia ('I'i0□), and the mold is heated to a high temperature, preferably 1000°C or higher, in a reducing atmosphere.
A high emissivity Invera 1 Nont Vf type in which the titania coating layer is a blackened lower oxide of titania (Ti-O2-χ) as described in Section 7.