Oxygen, Nitrogen, and Hydrogen in Refractory Metals

Summary

One of the most critical chemical specifications of titanium alloys is the hydrogen content. Too high of a

hydrogen content can cause hydrides to precipitate, which can lead to embrittlement and subsequent

cracking when the alloy is stressed. Hydrogen pickup typically occurs during downstream processing steps

such as heat treating, pickling, and cleaning.

The LECO ONH836 is a simultaneous oxygen, nitrogen, and hydrogen determinator that utilizes an electrode furnace, inert carrier gas, and both infrared and thermal conductivity detection to meet the analytical needs of the refractory metal industry. 

This application note was written specifically for use with the LECO ONH836 series determinator.

Procedure - Solid Samples

Instrument calibration/drift correction.

Place the calibration/drift standard in a *** Nickel Basket, and if applicable, place the sample into the appropriate autoloader position.

Press the Analyze button on the instrument screen. After a short delay, the loading head slide-block will open.

Note: samples using automation should be placed in the appropriate autoloader position before starting the

analysis sequence. Once the sequence has started, the automatic analysis will start and end automatically.

儀器的亮點(diǎn)和優(yōu)勢(shì)：

特點(diǎn)和優(yōu)勢(shì)

·爐頭區(qū)域LED照明系統(tǒng)

·爐頭快速拆裝的粉塵過濾裝置

·裝有自動(dòng)旁路閥的可快速拆裝氧水捕集裝置

·**的動(dòng)態(tài)流量補(bǔ)償（DFC）保證熱導(dǎo)池氣體流量、壓力恒定

高效脈沖爐冷卻系統(tǒng)

·強(qiáng)力內(nèi)循環(huán)水冷裝置熱交換效率

·雙直流風(fēng)扇保證持續(xù)冷卻，不受電壓波動(dòng)的影響

·***電極爐頭設(shè)計(jì)，提高脈沖爐

全自動(dòng)分析系統(tǒng)（可選）

·自動(dòng)清掃裝置

·20位或100位全自動(dòng)分析系統(tǒng)

·高效全自動(dòng)真空除塵裝置直接將粉塵排至儀器外部捕集器中，消除環(huán)境污染

改進(jìn)的紅外檢測(cè)池技術(shù)

·***紅外池的恒溫絕熱技術(shù)消除了外界環(huán)境溫度的干擾

·長(zhǎng)壽命的紅外發(fā)射光源和無(wú)漂移的電路設(shè)計(jì)保證紅外檢測(cè)池的長(zhǎng)期穩(wěn)定性

·氧高低雙量程采用3個(gè)碳紅外檢測(cè)器同時(shí)檢測(cè)一氧化碳和二氧化碳，保證準(zhǔn)確定量

Procedure - Solid Samples

Prepare the instrument as outlined in the operator's instruction manual.

Determine the instrument blank.

Login a minimum of 3 Blank replicates.

Press the Analyze button on the instrument screen. After a short delay, the loading head slide-block will open. Place a 502-344 Nickel Basket into the loading head.

Note: samples using automation should be placed in the appropriate autoloader position before starting the

analysis sequence. Once the sequence has started, the automatic analysis will start and end automatically.

Instrument calibration/drift correction

f. Clean the upper and lower electrode manually, or, if applicable, remove the crucible and press the analyze button to clean with the automatic cleaner.

g. Firmly place a graphite crucible on the lower electrode tip.

h. Press the Analyze button on the instrument screen, the lower electrode will close and the analysis sequence will start and end automatically.

i. Repeat steps 3b through 3h a minimum of three times for each calibration/drift standard used.

. Calibrate/drift following the procedure outlined in the operator's instruction manual.

新型氣路管道減少氣路連接閥，使得漏氣，斷路故障更少。氧氮?dú)浞治鰞x采購(gòu)

Sample Preparation

Typically, titanium and zirconium samples are chemically etched to remove surface contamination when oxygen and nitrogen are determined. However, etching can introduce hydrogen into the sample.

ASTM method E 1409 "Determination of Oxygen and Nitrogen in Titanium and Titanium Alloys by the Inert

Gas Fusion Technique", as updated in 1996, permits either etching or abrading (filing) of the test specimen.

ASTM E 1447 "Determination of Hydrogen in Titanium and Titanium Alloys by the Inert Gas Fusion Thermal

Conductivity/Infrared Detection Method" permits surface preparation by abrading (if necessary to remove

contamination). Differences in sample preparation present somewhat of a dilemma regarding simultaneous

determination of O, N, and H in titanium. However, abrading samples with a file to remove surface

contamination will yield accurate O, N, and H results. The ONH836 utilizes a high-power electrode furnace to quickly and efficiently release the target gases from within the sample, which allows for a very rapid simultaneous determination of oxygen, nitrogen, and hydrogen.