CN1016716B - Growth method of urea long-rod crystallon - Google Patents

Abstract

The present invention relates to a growth method for urea long-rod seed crystals, which adopts a solution temperature reduction method. Ethanolamine is added into methanol saturated solution of urea to enhance the growth speed of urea single crystals in the (001) direction so as to inhibit the expanding growth of a (110) cylinder surface, and thereof, the long-rod seed crystals having the growth speed in the (001) direction of about 4mm per day and the length larger than 185mm are obtained.

Description

Growth method of urea long-rod crystallon

The present invention adopts additive to change the growth method of urea single crystal habit.

Urea [(NH ₂) ₂CO] crystal is a kind of organic non-knot optical material of excellent property.Since people such as Kurtz reported urea single crystal nineteen sixty-eight laser radiation is produced second harmonic, the investigator did number of research projects for the urea single crystal that obtains the high-quality bulk both at home and abroad, and Zheng Daohong is in " growth of mountain macrocrystal " 1982.The not suprafacial normal growth speed of seed crystal is different when having reported general technology that urea single crystal grows on the fifth phase pointing out to carry out transparent growth with transparent crystals as seed crystal in different solution in alcoholic solution, but crystalline [111] the direction speed of growth≤0.3mm/ days United States Patent (USP) 4.537,990 adopt the growth of seed crystal clamping plate method restriction urea single crystal [111] face, and increase the growth of [110] and [110] face, and obtain 13 * 8 * 17mm ³Transparent single crystal, people such as HuangBing Rong report on the 15 volume second phase of " artificial lens " June in 1986 grows from alcoholic solution with long-rod crystallon to growing technology with special sincere mask pattern restriction Z and is of a size of 44 * 36 * 68mm ³Large single crystal.In sum, the most aqueous solution cooling methods that adopt of current urea single crystal growth technique, and enlarge the transparent size of crystal [110] face and [110] face with the growth of physical method restriction Z direction, to adapt to the requirement that laser technology is used, the acquisition of seed crystal is to go out 1.5 * 1.5mm by spontaneous crystallization or with the crystal that has large-size now in [110] face cleavage in its method ²Thin excellent strip crystal, but the former gained generally is that acicular point is brilliant, short and thin, be awkward, how latter's gained seed crystal owing to a generation is shortened than a generation by its length that limits of clamping plate, obtains the long-rod crystallon than long several times tens times of existing seed crystal fast, being an important topic in the urea single crystal growth, also is purpose of the present invention.

The present invention is with the aqueous solution cooling method urea single crystal of growing, but changed the practice that in the past limits the growth of Z direction, adopt additive to impel the quick growth of [001] direction to obtain the excellent crystal of length with the growth of restriction [110] face greater than 185mm, this method is to be primary solvent, to form mixed solvent by adding 10～50g ethylene glycol and 1-5g thanomin additive in every 100g methyl alcohol with organic methyl alcohol, add excessive solid top grade urea raw material again, under 30～50 ℃, be mixed with supersaturated solution, balance is 36 hours after filtration, seed crystal to be put.Seed crystal adopts the urea crystal of large-size to go out about 1.5 * 1.5mm in [110] face cleavage ²About, the transparent rectangular crystal of no significant defect bores two apertures at middle portion then, polishes with the wet silk of ethanol and dries, then use with the inoperative rope of solution to be fixed on the mask pattern, put to be preheating in the baking oven and put into above-mentioned growth from solution again with solution is synthermal.In process of growth, should strict its degree of supersaturation of control be cooling rate.In the general initial growth stage, cooling every day amount is advisable with 0.03～0.1 ℃, along with crystal is grown up, cooling every day amount can increase to 0.05～0.2 ℃, even can reach 0.2～0.5 ℃ at last, carry out the average speed of growth about 4mm every day of its [001] direction by above method.

The present invention has overcome urea crystal and has been difficult to long problem in [001] direction, change the method for the restriction Z direction growth of in the past passing through usefulness, in the saturated solution of urea-methyl alcohol, add thanomin, impel the urea seed crystal in the growth of [001] direction fast transparent, 10 times long-rod crystallon is grown in acquisition than the seed crystal of spontaneous crystallization.The present invention be advantageous in that when adopting long-rod crystallon to carry out single crystal growing, under same appointed condition, by every month every groove growing single-crystal 13.5mm ³, bring up to 50mm ³, 3.7 times of the growth rates of raising urea crystal.

Get AR level methyl alcohol 1557 grams under 40 ℃, add 600 gram AR level urea raw materials, add 40 gram thanomins then, constant temperature stirs 36 hours after-filtration in 2500ml mill sealed glass jars, and after the Overheating Treatment, constant temperature is treated crystal seed down in 40.5 ℃ thermostatic bath.

With more transparent complete urea single crystal, the face cleavage goes out 10 * 1.5 * 53mm in [110] ³Rectangular crystal bore two apertures as seed crystal and on [110] face, mill is done on the wetting silk of ethanol, be fixed on the sincere mask pattern of glass with nylon wire, put into and put into above-mentioned saturated solution after 42 ℃ of baking oven preheatings and grow, and cool the temperature to rapidly than 39.98 ℃ of low 0.02 ℃ of saturation point temperature and recover again to grow and open Crystal Rotation after a few hours with 30 rev/mins rotating speed to help crystal, make [111] and [111] face of seed crystal revert to awl, after two days, every day is with 0.03～0.1 ℃ cooling degree, reduce to 39 ℃ gradually, again with every day 0.1～0.5 ℃ of cooling amount grow fast about 25 days, when temperature is reduced to below 30 ℃, can take out crystal when extracting solution equilibria out, obtain 12 * 12 * 150mm to room temperature ³Urea long-rod crystallon.

Claims (1)

1, a kind of growth method of urea long-rod crystallon, with aqueous solution cooling method growth urea monocrystalline, is growth media with urea at the saturated solution of methyl alcohol and ethylene glycol, with being cleaved into the fine strip shape urea crystal as seed crystal along [110] face, under 40-45 ℃ of temperature, to grow, cooling rate is 0.03 ℃-0.5 ℃/day, it is characterized in that in saturated solution, adding thanomin as the growth of restriction [110] crystal face, quicken the additive of crystal [001] direction growth, methyl alcohol, ethylene glycol, thanomin three proportioning is:

Methyl alcohol: 100 grams

Ethylene glycol: 10-50 gram

Thanomin: 1-5 gram