JPH01209355A - Manufacture of oxygen sensor element - Google Patents
Manufacture of oxygen sensor elementInfo
- Publication number
- JPH01209355A JPH01209355A JP63032815A JP3281588A JPH01209355A JP H01209355 A JPH01209355 A JP H01209355A JP 63032815 A JP63032815 A JP 63032815A JP 3281588 A JP3281588 A JP 3281588A JP H01209355 A JPH01209355 A JP H01209355A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- coating
- oxygen sensor
- coating layer
- spinel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000001301 oxygen Substances 0.000 title claims description 29
- 229910052760 oxygen Inorganic materials 0.000 title claims description 29
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims description 23
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 239000010410 layer Substances 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims abstract description 10
- 238000000576 coating method Methods 0.000 claims abstract description 9
- 238000001816 cooling Methods 0.000 claims abstract description 9
- 239000011248 coating agent Substances 0.000 claims abstract description 7
- 239000007784 solid electrolyte Substances 0.000 claims description 14
- 239000011241 protective layer Substances 0.000 claims description 2
- 239000011247 coating layer Substances 0.000 abstract description 23
- 239000007789 gas Substances 0.000 abstract description 13
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 abstract description 10
- 229910052596 spinel Inorganic materials 0.000 abstract description 9
- 239000011029 spinel Substances 0.000 abstract description 9
- 230000035699 permeability Effects 0.000 abstract description 6
- 230000004043 responsiveness Effects 0.000 abstract description 6
- 238000007747 plating Methods 0.000 abstract description 5
- 229910052697 platinum Inorganic materials 0.000 abstract description 5
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 abstract description 4
- 238000005507 spraying Methods 0.000 abstract description 3
- 239000002253 acid Substances 0.000 abstract description 2
- 238000005530 etching Methods 0.000 abstract description 2
- 238000010438 heat treatment Methods 0.000 abstract description 2
- 229910002077 partially stabilized zirconia Inorganic materials 0.000 abstract description 2
- 239000007787 solid Substances 0.000 abstract 2
- PWKWDCOTNGQLID-UHFFFAOYSA-N [N].[Ar] Chemical compound [N].[Ar] PWKWDCOTNGQLID-UHFFFAOYSA-N 0.000 abstract 1
- 230000002708 enhancing effect Effects 0.000 abstract 1
- 238000007750 plasma spraying Methods 0.000 description 4
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- WMWLMWRWZQELOS-UHFFFAOYSA-N bismuth(iii) oxide Chemical compound O=[Bi]O[Bi]=O WMWLMWRWZQELOS-UHFFFAOYSA-N 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000007772 electroless plating Methods 0.000 description 1
- VQCBHWLJZDBHOS-UHFFFAOYSA-N erbium(III) oxide Inorganic materials O=[Er]O[Er]=O VQCBHWLJZDBHOS-UHFFFAOYSA-N 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005382 thermal cycling Methods 0.000 description 1
- 238000007751 thermal spraying Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Measuring Oxygen Concentration In Cells (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、酸素センサ素子の製造法に関・し、特に耐
久性の向上を図ったコーティング層を有する酸素センサ
素子の製造法に関するものである。[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing an oxygen sensor element, and particularly to a method for manufacturing an oxygen sensor element having a coating layer with improved durability. be.
（従来の技術）
従来、酸素イオン導電性の固体電解質を用い、酸素濃淡
電池の原理により、内燃機関等から排出される排気ガス
中の酸素濃度を測定するものとしていわゆる酸素センサ
素子が知られている。(Prior Art) Conventionally, so-called oxygen sensor elements have been known as devices that use an oxygen ion conductive solid electrolyte and measure the oxygen concentration in exhaust gas discharged from internal combustion engines, etc., based on the principle of an oxygen concentration battery. There is.
かかる酸素センサ素子としては、例えば有底円筒状のイ
ツトリア添加ジルコニア磁器等を酸素イオン透過性の固
体電解質として、この固体電解質の内外面に、例えば白
金等の電極を付与したものが一般的であり、内面の電極
を大気と連通させて基準酸素濃度の電極とする一方、外
面の電極を被測定ガスである排気ガス中に曝して測定電
極とすることによって排気ガス中の酸素濃度を測定する
しくみになっている。Such an oxygen sensor element is generally one in which an oxygen ion-permeable solid electrolyte is made of, for example, a bottomed cylindrical yttria-doped zirconia porcelain, and electrodes of, for example, platinum are provided on the inner and outer surfaces of the solid electrolyte. , A mechanism for measuring the oxygen concentration in exhaust gas by connecting the inner electrode with the atmosphere and using it as the reference oxygen concentration electrode, while exposing the outer electrode to the exhaust gas, which is the gas to be measured, and using it as the measurement electrode. It has become.
このような酸素センサ素子には、一般に外側電極を保護
するために、スピネル等のコーティングが施されている
。Such oxygen sensor elements are generally coated with spinel or the like to protect the outer electrodes.
（発明が解決しようとする問題点）
しかしながら、かかるコーティング層は、酸素センサが
内燃機関の回転数の変動に伴って、サーマルサイクルを
受けるので、クランクが発生し、コーティング層が白金
等の電極から剥がれることがある。コーティング層が剥
がれると外側電極層が露出し、酸素センサの使用中に還
元性排気ガスにさらされるため、この露出部分から外側
電極層が減耗して、酸素センサ素子の出力電圧が低下す
るという問題点が発生する。また、−ｉにコーティング
層が厚くなると、ガス透過性が小さくなるため、白金等
よりなる電極の減耗に対しては良い効果を与えるが、応
答性が悪くなる問題点がある。(Problem to be Solved by the Invention) However, since the oxygen sensor is subjected to a thermal cycle due to fluctuations in the rotational speed of the internal combustion engine, cranking occurs, and the coating layer is removed from the platinum or other electrode. It may peel off. When the coating layer peels off, the outer electrode layer is exposed and exposed to reducing exhaust gas during use of the oxygen sensor, which causes the outer electrode layer to wear away from this exposed portion, resulting in a decrease in the output voltage of the oxygen sensor element. A point occurs. In addition, when the coating layer becomes thicker than -i, the gas permeability decreases, which has a good effect on the wear and tear of the electrode made of platinum or the like, but there is a problem in that the responsiveness deteriorates.
この発明は、上記した問題点等を解消し、コーティング
層の内部応力を緩和し、サーマルサイクル中における耐
久性を向上させると共にコーティング層が厚くても応答
性の良い酸素センサ素子の製造法を提供することを目的
とする。This invention solves the above-mentioned problems, relieves the internal stress of the coating layer, improves durability during thermal cycling, and provides a method for manufacturing an oxygen sensor element that has good responsiveness even when the coating layer is thick. The purpose is to
（問題点を解決するための手段）
すなわちこの発明は、酸素イオン導電性固体電解質の外
面に設けられた電極層上に耐熱性無機質コーティングの
保護層を形成するプラズマコーティングしを複数回行う
間に少なくとも一回の該酸素イオン導電性固体電解質を
冷却することを特徴とする。(Means for Solving the Problems) That is, the present invention provides a method for forming a protective layer of a heat-resistant inorganic coating on an electrode layer provided on the outer surface of an oxygen ion conductive solid electrolyte while performing plasma coating multiple times. The method is characterized in that the oxygen ion conductive solid electrolyte is cooled at least once.
（作 用）
本発明では、素子１ヶ当り複数回のスピネルのプラズマ
コーティングを繰返えし行う間に、酸素センサ素子を少
なくとも１回冷却することにより、冷却を施す前のコー
ティング層と冷却を施した後のコーティング層との間に
ミクロ的な間隙が生じ、この間隙がコーティング層に発
生する内部応力を緩和したり、ガスの透過性が良（なる
ため、酸素センサ素子のサーマルサイクルに対する耐久
性が向上し、応答性が改善される。(Function) In the present invention, by cooling the oxygen sensor element at least once while repeating spinel plasma coating multiple times per element, the coating layer and the cooling layer before cooling are cooled. Microscopic gaps are created between the coating layer and the coating layer, and these gaps alleviate the internal stress generated in the coating layer and improve gas permeability (which improves the oxygen sensor element's durability against thermal cycles). performance and responsiveness.
（実施例） 以下、本発明の詳細な説明する。(Example) The present invention will be explained in detail below.
本発明の酸素センサ素子に用いられる固体電解質は、酸
素イオン導電性を有するもので構成され、例えば組成と
してＹｂｚＯ：＋、 ５ＣＺＯ３，Ｃａｂ、 ＭｇＯ，
Ｔｈ０ｚ。The solid electrolyte used in the oxygen sensor element of the present invention is composed of one having oxygen ion conductivity, and has a composition such as YbzO:+, 5CZO3, Cab, MgO,
Th0z.
Ｃｅ０ｚ等を添加したＺｒ０ｚ； Ｃａｂ、 Ｌａｇ’
３等を添加したＣｅＯ，； Ｅｒ２Ｏ３，ＳｒＯ等を添
加したＢｉ２Ｏ３；あるいはＹ２Ｏ３等を添加したＴｈ
Ｏ□である。特に、機械的強度、温度特性上Ｙ２Ｏ３等
を含むＺｒＯ□（完全安定および部分安定を含む）が好
ましい。Zr0z added with Ce0z etc.; Cab, Lag'
CeO added with 3 etc.; Bi2O3 added with Er2O3, SrO etc.; or Th added with Y2O3 etc.
It is O□. Particularly preferred is ZrO□ (including completely stable and partially stable) containing Y2O3 etc. in terms of mechanical strength and temperature characteristics.
このような組成原料を有底円筒状あるいは平板状に成形
し、焼成して固体電解質素子を製造する。 次に固
体電解質素子の内外表面に金属層を形成して電極とする
。電極の形成は例えば無電解めっきによって行われる。A solid electrolyte element is manufactured by forming such raw materials into a bottomed cylindrical shape or flat plate shape and firing. Next, metal layers are formed on the inner and outer surfaces of the solid electrolyte element to form electrodes. The electrodes are formed, for example, by electroless plating.
めっき処理後、熱処理を施し、電極表面の保護のために
、例えばスピネル粒子のプラズマ溶射を施す。このプラ
ズマ溶射の回数は、例えば２〜７回程度が良く、−回の
溶射によって形成されるスピネルコート層の厚さは例え
ば２０〜３０μｍである。After the plating process, heat treatment is performed, and plasma spraying of spinel particles, for example, is performed to protect the electrode surface. The number of times of this plasma spraying is preferably about 2 to 7 times, and the thickness of the spinel coat layer formed by the -times of spraying is, for example, 20 to 30 μm.
したがって、層厚が４０〜２１０μｍのコーティング層
が得られる。本発明は、このプラズマ溶射の間に少なく
とも一回、好ましくは各回毎に冷却を行う。冷却の方法
は、プラズマ溶射後プラズマ溶射チを固体電解質素子か
ら離して溶射層が凝固する温度、例えばスピネル粒子を
コーティング層とする場合は、７００″Ｃ以下にする。A coating layer with a layer thickness of 40 to 210 μm is thus obtained. The present invention provides cooling at least once during this plasma spraying, preferably each time. The cooling method is such that after plasma spraying, the plasma sprayed chip is separated from the solid electrolyte element to a temperature at which the sprayed layer solidifies, for example, when spinel particles are used as the coating layer, the temperature is 700''C or less.
コーティング層に良好な気孔を有させるためには、室温
から３００°Ｃの範囲に冷却することが好ましい。コー
ティング層は冷却毎にミクロ的な間隙が生じるためコー
ティング層の内部応力が緩和されると共にガスの透過性
が良くなる。かくして電極層の上層部には内部応力が小
さく、ガス透過性の良好なコーティング層が形成される
ので、使用中にサーマルサイクルを受けてもクラックが
発生せず、耐久性が良く応答性に優れた酸素センサ素子
が得られる。In order to have good pores in the coating layer, it is preferable to cool the coating layer to a temperature ranging from room temperature to 300°C. Since microscopic gaps are generated in the coating layer each time it is cooled, internal stress in the coating layer is relaxed and gas permeability is improved. In this way, a coating layer with low internal stress and good gas permeability is formed on the upper layer of the electrode layer, so it does not crack even when subjected to thermal cycles during use, and has good durability and excellent responsiveness. An oxygen sensor element is obtained.
実施例１
まず、有底円筒状Ｙ２Ｏ３を添加した部分安定化ジルコ
ニア固体電解質素子を、その表面の汚れを取り除くため
に脱脂処理をした後、フッ酸等の酸でエツチング処理を
行い、次いで無電解白金めっきを施し、厚さ１．０μｍ
のめっき層を得た。このめっき層が施された固体電解質
素子を水洗した後、１２０ ”Ｃで１時間乾燥し、めっ
き層を固体電解質の下地に密着させるため７００°Ｃの
大気中で３０分熱処理をした。この後、固体電解質素子
に数種の平均粒径を有するスピネル（八１□０１．・Ｍ
ｇ０）をアルゴン／窒素プラズマ法にて溶射した。この
ようにして得られた酸素センサ素子を金属ケーシングで
組立てプロパンバーナー法にてガス温度４００°Ｃでの
起電力が６００ ｍＶから３００ ｍＶに変化する応答
時間を測定した。またエンジンにて排気ガス温度が３０
０°Ｃから１０５０°Ｃへ、１０５０”Ｃから３００°
Ｃへ交互に変化するサーマルサイクルテストを１５００
サイクル行って、テスト終了後にセンサを解体し、コー
ティング層のクラック発生の有無を４０倍の実体顕微鏡
にて検査した。これらの結果を第１表に示す。Example 1 First, a partially stabilized zirconia solid electrolyte element containing bottomed cylindrical Y2O3 was degreased to remove dirt from its surface, then etched with an acid such as hydrofluoric acid, and then subjected to electroless etching. Platinum plated, thickness 1.0μm
A plating layer was obtained. After washing the solid electrolyte element with this plating layer applied with water, it was dried at 120"C for 1 hour, and heat treated in the atmosphere at 700°C for 30 minutes to make the plating layer adhere to the solid electrolyte base. After this, , spinel (81□01.・M
g0) was thermally sprayed using an argon/nitrogen plasma method. The oxygen sensor element thus obtained was assembled with a metal casing, and the response time for the electromotive force to change from 600 mV to 300 mV at a gas temperature of 400°C was measured using a propane burner method. Also, the exhaust gas temperature in the engine is 30
0°C to 1050°C, 1050”C to 300°
1500 thermal cycle tests alternating to C
After the cycle was completed, the sensor was disassembled and the coating layer was inspected for cracks using a stereomicroscope with a magnification of 40 times. These results are shown in Table 1.
第１表から明らかなようにスピネルコーティングの溶射
の途中に、少なくとも１回の冷却を施したセンサはいず
れのサンプルもコーティングにクラックが発生せず、応
答性も冷却しなかったサンプルに比較して良好であった
。As is clear from Table 1, none of the samples in which the spinel coating was cooled at least once during thermal spraying exhibited any cracks in the coating, and the response was significantly lower than in the samples that were not cooled. It was good.
（発明の効果）
以上の説明から明らかなように本発明は複数回のプラズ
マコーティング処理中に冷却を少なくとも１回施すこと
により、コーティング層には冷却毎にミクロ的な間隙が
生じるため、コーティング層の内部応力を緩和し、かつ
ガス透過性が良くなるので、サーマルサイクルに対する
耐久性が良好で、応答性に優れた酸素センサ素子を得る
ことができ、産業上利用の可能性が極めて大である。(Effects of the Invention) As is clear from the above description, the present invention provides cooling at least once during multiple plasma coating processes, so that micro gaps are created in the coating layer each time the coating layer is cooled. Since the internal stress of the oxygen sensor is alleviated and the gas permeability is improved, it is possible to obtain an oxygen sensor element that has good durability against thermal cycles and excellent responsiveness, and has extremely high potential for industrial use. .
Claims (1)
極層上に耐熱性無機質コーティングの保護層を形成する
プラズマコーティングを複数回行う間に少なくとも一回
の該酸素イオン導電性固体電解質を冷却することを特徴
とする酸素センサ素子の製造法。1. Cooling the oxygen ion conductive solid electrolyte at least once during multiple plasma coatings to form a protective layer of heat-resistant inorganic coating on the electrode layer provided on the outer surface of the oxygen ion conductive solid electrolyte. A method for manufacturing an oxygen sensor element characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63032815A JPH01209355A (en) | 1988-02-17 | 1988-02-17 | Manufacture of oxygen sensor element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63032815A JPH01209355A (en) | 1988-02-17 | 1988-02-17 | Manufacture of oxygen sensor element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01209355A true JPH01209355A (en) | 1989-08-23 |
Family
ID=12369331
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63032815A Pending JPH01209355A (en) | 1988-02-17 | 1988-02-17 | Manufacture of oxygen sensor element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01209355A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0621348A1 (en) * | 1993-04-19 | 1994-10-26 | Sulzer Metco (US) Inc. | Fixture and method for cooling tubular substrate during thermal spraying |
| US6544586B1 (en) | 1998-02-16 | 2003-04-08 | Ngk Spark Plug Co. Ltd. | Method for manufacturing gas sensor element |
| JP2007248123A (en) * | 2006-03-14 | 2007-09-27 | Ngk Spark Plug Co Ltd | Gas sensor element and manufacturing method of gas sensor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5489686A (en) * | 1977-12-27 | 1979-07-16 | Hitachi Ltd | Oxygen density detector |
| JPS5557145A (en) * | 1978-10-23 | 1980-04-26 | Toyota Motor Corp | Manufacture of oxygen sensor element |
-
1988
- 1988-02-17 JP JP63032815A patent/JPH01209355A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5489686A (en) * | 1977-12-27 | 1979-07-16 | Hitachi Ltd | Oxygen density detector |
| JPS5557145A (en) * | 1978-10-23 | 1980-04-26 | Toyota Motor Corp | Manufacture of oxygen sensor element |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0621348A1 (en) * | 1993-04-19 | 1994-10-26 | Sulzer Metco (US) Inc. | Fixture and method for cooling tubular substrate during thermal spraying |
| US6544586B1 (en) | 1998-02-16 | 2003-04-08 | Ngk Spark Plug Co. Ltd. | Method for manufacturing gas sensor element |
| JP2007248123A (en) * | 2006-03-14 | 2007-09-27 | Ngk Spark Plug Co Ltd | Gas sensor element and manufacturing method of gas sensor |
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