DE1596845C - Glass with a small temperature coefficient of transit time for ultrasonic waves - Google Patents

Description

I 596 845

1 2

The invention relates to a glass with small.

Temperature coefficients of the transit time for ultrasonic ^ _n . , _DUn . ,, - "<- <; _A u ->-> n

π j. . ι Ji, - γ- · ι 1 IWt ~ γ γ Dv- * H DlS ο, J JU DIS ZZ.U

waves and is specially designed for transversal »a., ■.

Waves of about 4 MHz. As ₂ O ₃ and / or

It is well known that glass is used as a material for 5 ^{2 3} ''''

Can use delay lines. Depending on the marriage- When using this glass is achieved that in

Mixer composition of the glass results in a temperature range between -20 and + 7O ⁰ C die

Delay times of 2.7 to 4.6 microseconds run through a minimum and the fluctuation

per centimeter of path length if you transverse the delay time in the temperature range ± 20 ° C

Stimulates sound waves. For microwave technology 10 of this minimum temperature is less than 8 × 10 ^-5

are lines with delay times up to some of the transit time.

Milliseconds has been developed. It has also been found that for certain applications the minimum of the running time will come up to date in the range of: for color television reception and in calculating machines room temperature ± 10 ⁰ C it is important that the content for the delay line is an essential additional factor LiO ₂ O to 2 percent by weight of Na ₂ O ₁ O up to the condition: the transit time of the ultrasonic waves 12 percent by weight, the K ₂ O content of O to 20Ge 'must be constant weight percent over a larger temperature range and the ratio must be. For example, for the recipient of the coloring. . television according to the PAL system required that the ^Σ alkali oxide mole percent

relative change in transit time »± - ^ - <2 ■ 10- / ⁰ C ^{20 Ti} ° ^{2 mol percent}

is in a temperature range of about 10 to 6O ⁰ C. is between 3.0 and 5.5.

This requirement is very high when one considers, Furthermore, it has proven to be advantageous that the

that the relative change in the running time for glass and the sum of TiO ₂ and PbO 4 to 8.5 mole percent

for other substances a value of the order of magnitude is 25, with the TiO ₂ content 1.5 to 5 mole percent

Order 1 · 10 ~ ⁴ / ° C. and the PbO content is 0 to 6 mole percent.

The best known from the literature so far. The table shows six examples of combinations

Delay lines consisted of a glass. Settlements in percent by weight for glasses according to

listed with a temperature constancy of the running time of the invention.

5.18 x 10 ~ ⁶ / ° C. Other glasses for ultrasonic delay 30 These glasses have in the field of room tempering lines are from British Patent 990 849 temperature a minimum of the transit time, the curve of US Pat. No. 3,154,425 being known. This temperature dependence is very flat. In addition to glasses, they have a high lead content of 14.7 and the chemical composition of the table contains up to 16.7 mol percent PbO. This information about the expansion coefficient α, the high lead content leads to a relatively high thermal transformation temperature Tg, the specific expansion, to a relatively high density weight s, the temperature minimum of the transit time T ₀ and to a relatively low transformation temperature as well as the maximum relative change in runtime. Thus, these known glasses for encryption Az -vvrn a it, wp \ application in many modern electronic devices, ~ T between (T _0-20 C) and (T ₀ + 20 C). where a low weight of the electronic 40 To stabilize the crystallization of the inventive component and the possibility of soldering on according glasses, it is permissible, up to 2 weight of the ceramic transducer is important, not satisfied- percent alkaline earth oxides, CdO, ZnO, Al ₂ O ₃ , ZrO ₂ , WO ₃ . . 'to admit, the sum of 5 percent by weight not. The object of the invention is a glass for ultrasound may not exceed the temperature stability of the delay lines, which significantly affect a very short 45 transit time. For the high temperature coefficient of the transit time for ultrasonic constancy of the transit time, it is important that the glasses have waves, the aforementioned requirements for melting and molding carefully and the disadvantages of the aforementioned cool, ie at speeds of 1.0 to 0 , 5 ⁰ C glasses does not have. per hour because this reduces the after-effects. The advantages of the glass with the following composition: written glasses, compared to glasses with larger

Gh- ^rem ß ^'e' 8 ^{ena '1' SmC} * the smaller thermal Ausprozent percent ^S ~ elongation and higher transformation temperature, SiO ₂ + B ₂ O ₃ .... 75 to 85 65 to 83 the smaller density. The first two properties where B ₂ O ₃ ..... 0 to 4 0 to 3 55 are for soldering the ceramic transducers, the alkali oxides ..... 8 to 14 9.0 to 20 last for a low weight of the electronic TiO ₂ 1.5 to 5.0 2.0 to 6.0 'component favorable.

Compositions in percent by weight

Oxides

SiO ₂ B ₂ O ₃ Li ₂ O Na ₂ OK ₂ O

74.7

82.5
12.0

80.2

1.5
9.6

76.9 10.8

66.3
2.0

7.5
2.6

66.4 2.0

7.5

2.5

68.4

7.5 2.6

596

continuation

Oxides 1 ■ 2 3 4th 5 6th • 7 ZnO 1 O PbO 5.0 5.0 4.0
4.2 7.9
3.6 18.4
2.7 15.2
1.0
3.0
1 1 18.5 Al, O, 0.4. 0.5 0.5 0.8 0.5 0.3 2.7 TiO ₂ 77.3 56.8 58.6 59.5 65.2 61.3 0.3 ZrO, 573 538 475 508 514 529 71.2. As, O, 2.40 2.38 2.45 2.53 2.79 2.73. 490 Sb ₂ O ₃ 65 55 40 75 42 18th 2.77 α · 10 ⁷ (-30 to + 7O ⁰ C) ... 1.5 ■ 10 " ⁵ 1.6 · ΙΟ " ⁵ 6.2 · ΙΟ " ⁵ 6.2 ■ 10 ~ ⁵ 4.7 x 10 " ⁵ 3.9 · ΙΟ " ⁵ 30th Tg ⁰ C .. .. 6.2 x 10 " ⁵ s T _n ° C Az. ' ^T o - ²⁰ ° C 1. J ₀ + 2O ⁰ C

Claims (6)

Claims: ' 1. Glass with a small temperature coefficient of Run time for ultrasonic waves, preferably for transverse waves of about 4 MHz, marked by the following composition: Mole percent weight percent SiO ₂ + B ₂ O ₃ ... '. 75 to 85 65 to 83 Alkali oxides 8 to 14 9.0 to 20 TiO ₂ + PbO .... 4 to 8.5 5.0 to 22.0 As ₂ O ₃ and / or Sb ₂ O ₃ 0.1 to 0.3 0.3 to 1.5 B ₂ O ₃ O to 4 O to 3 TiO ₂ 1.5 to 5.0 2.0 to 6.0 2. Glass according to claim 1, characterized in that it Mole percent weight percent Li ₂ OO to 4 O to 2 Na ₂ OO to 12 O to 12 K ₂ OO to 14 O to 20 contains and the mole percent ratio Σ alkali oxides . TiO ₂ 6o is between 3.0 and 5.5. , 3. Glass according to claim 1 or 2, characterized in that the TiO ₂ content is 1.5 to 5 mol percent and the PbO content is 0 to 6 mol percent. 4. Glass according to claim 1 or 2, characterized in that it consists of Mole percent weight percent SiO ₂ 81.9 "" 74.7 K ₂ O 13.9 19.9 TiO ₂ 4.1 5.0 Sb ₂ O ₃ 0.1 0.4 consists. 5. Glass according to claim 1 or 2, characterized in that that it is off Mole percent weight percent SiO ₂ 78.9 x 66.3 B ₂ O ₃ 2.0 2.0 Na ₂ O: ... 8.6 7.5 K ₂ O 2.0 2.6 PbO 5.9 18.4 TiO ₂ 2.4 2.7 As ₂ O ₃ 0.2 0.5 consists. 6. Glass according to claim 1 or 2, characterized in that it consists of Mole percent weight P ^{r0! Tent} SiO ₂ 77.9 66.4 " B ₂ O ₃ 2.0 2.0 Na ₂ O 8.5 7.5 K ₂ O 1.9 2.5 PbO 4.8 15.2 TiO ₂ . 2.6 3.0 v ZrO ₂ 0.6 1.1 Sb ₂ O ₃ 0.1 0.3 exists and as stabilizers ·. " zno. ^Molp o7 ^{nt G} Al ₂ O ₃ 0.7 1.0 contains.