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Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing, UT

Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing

Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing

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Lithium Sulphate LiSO 4 , grows from Lithium Sulphate solution by<br />

evaporation.<br />

Advantages:<br />

1. Lithium Sulphate is the most efficient receiver of ultrasound<br />

2. It has low electric impedance<br />

3. Operate well at low voltage<br />

4. it does not age<br />

5. it has very good resolution<br />

6. crystals are easily damp and give a short pulse length<br />

Disadvantage<br />

1. It dissolves in water<br />

2. It breaks easily<br />

3. It decomposed at temperature above 130°C (what is Curie temperature?)<br />

All of which make it unsuitable <strong>for</strong> industrial used, except <strong>for</strong> medical<br />

ultrasonic where the temperature restriction is not a concern.

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