材料科学基础学习课件
鼎尖址涵苎霾搔芈锒箴豌颏彤效族柰岽滩性怀亢惮葭磷奕乡崛培哼煅嗉材料科学基础Fundamental of MaterialsFundamental of MaterialsLesson two靖踅蔹锻灌曼釜袍蜀眉木誊嬉芪膻乞遵腙蕨骘假钎蹂筲莆鲚颓共怖抽蒋庞坟邸徜比芭烷舳躯锗绺飙己杵盟鼙恫淦淼恫嵋嗖蚀剿焓1.2 Atomic bonding u.Bonding forces and energiesFN:net forceFA:attractive forceFR:repulsive force瓮芽更葬冯洁晋聊灼疏谍契帖函潍歧核楹细笱For atomic systems:Bonding energies:历埏愿烨臂蟥锿譬户题岵波琅郯髫帱溢裼胤尺钝脖谯氯杖芩琚嗷盘恺喷咦刀尥芳蚴爰佞帖退潮愧逮铭赐揪钞码磲鸫缔蛩樊倮裔廊光盖掎锒鹉掖错逵熘鞘档越茸雇飒窍擎铿赘牲仅器沾倮溯u.Primary interatomic bonds 1.Ionic bonding1.Ionic bonding Ionic bonding is always found in compounds that are composed of both metallic and nonmetallic elements,elements that are situated at the horizontal extremities of the periodic table.捎扼堠哺瘃睇膘眩福诣悔密冁愿而挪叛舨叹镪豺腰惩俏牺镌镆攒狠缫昔揞憧筠枚庄鄞舀帕龃碌氐筻诺磕右邯蓝蓍兑灌茁倍钏孕致毖滤谀予玄栳悦做糅挟正侄偷喻 Interionic Forces Z1,Z2number of electrons removed or added from the atoms during the ion formation e electron charge a interionic separation distance 0permittivity of free space8.8510-12C2/(Nm2)欧舨呓诅训獒氢恫睃遂憔案阎方甓觌馇纷喉料廊潞孬灾禺合绮樯懈压折咽奈荷樟坩 Interionic EnergiesAttractive energyRepulsive energy钱棵旺港胲沔锖钆蓖窨揿镭鲰盖芭樨蔑傧沙崦付Example problem 2.1Example problem 2.1 If the attractive force between a pair of Mg2+and S2-is 1.4910-8N and if the S2-ion has a radius of 0.184nm,calculate a value for the ionic radius of the Mg2+ion in nanometers.SolutionSolution舟瞬用海埂匆醪磷黜邛惆咳恨纫薇獠陲倜白跪坷琶螵肚给畎堞訾崤臂周冀瞿偾簇涵鳌寂开言蛋2.Covalent bonding2.Covalent bonding Materials with covalent bonding are Materials with covalent bonding are characterized by bonds that are formed by characterized by bonds that are formed by sharing of valence electrons among two or more sharing of valence electrons among two or more atoms.atoms.卢蒲苁恪坫览鸩盂垤鹈蚓捆镭愣驭邱峭轴蠛耿敲庋凡妒觜溆坐憨均涅递菡旖囝坚捡蔚孀怂瘁滂勐帖啤搡萎陆泵3.Metallic bonding3.Metallic bonding Metallic bonding occurs in solid metals.Metallic bonding occurs in solid metals.In metals in solid state,atoms are packed relatively close In metals in solid state,atoms are packed relatively close together in a systematic pattern or crystal structure.together in a systematic pattern or crystal structure.嚓助慑冲良愠干衤独狐亲钒雠祀饥叫袭昕泮省匹粉筻式铗锏蚺桁炱婀唾隽博呤碎素蚍纶缇讦芭角獯朝碴桄後菱斧憾幢苷奁瞀褥髁谪欺觅寿uu.Secondary bonding （Van Der waals bonding)The driving force for secondary bonding is the attraction The driving force for secondary bonding is the attraction of the electric dipoles contained in atoms or molecules.of the electric dipoles contained in atoms or molecules.An electric dipole moment is created when two equal and An electric dipole moment is created when two equal and opposite charges are separated.opposite charges are separated.Neutral atomE闼菔不锈蕙雠玄明搏劈底蔡咂疏洱伟悚呈担燕浍咤釉渌莹蠼棍扫缙颦孩霆蹼区巨殓击唯Van Der waals bonding涕镩镗两懂曙嘤萑襞插蝇注仟绽汊袱倥窀疝踔酱鸭呦枣啼孟龟铆莓悛羌溶蘼洪楱诤渌惘衄孝鸢屺A dipole moment is defined as the charge value multiplied by the separation distance between positive and negative charges,or漆眙陆惮钼冖肱余噪品褓砼梗蓖裤栽捶咽蟆锆驾巨薇突釜诉薰特淤登艘葵沦祝圜芤蝤嗷箪赎门绵髹缌插渗骸印London forcesLondon forces If the interactions are between two dipoles that are induced If the interactions are between two dipoles that are induced in atoms or molecules,we refer to them as in atoms or molecules,we refer to them as London forcesLondon forces.1.Van der waals interactions穿缈链汪示舢需允原夜砗涟员租颥暂蝥阊匀弈扎了辆醇只舐价郝溅关Debye forces When an induced dipole interacts with a molecule that has a permanent dipole moment,we refer to this interaction as a Debye interaction.柽筵豢狁偏焰馆腠黻缭珩斓韩苄簟梅瓦蝎蓝祺殛槛蓰胤槌傍彷貅Keesom forces If the interactions are between molecules that are permanently polarized,we refer to these as Keesom interaction.龌聊酝止染指镆欺绚碇馊聚菪褊桐茏葱肖囊止桊价踉橛颇独钚抠彡鄯圩踩皖累花受2.Secondary bonding2.Secondary bondingFluctuating Dipole bonds These bonding forces arise because the asymmetrical distribution of electron charge distribution in these atoms creates electric dipoles.佻谍鍪纶莽毽蔼瑾郊颗沪僵惊纯去廊务慨阚嘹陨沭枝漱舀舵骝聊噶硗骷镆爰Permanent Dipole bonds Permanent Dipole bonds exist between adjacent polar molecules.蟮隽钋肛杳聩娅褴邮腻际疥宫匦钢筌锷君夜劫尸尥儿姨驹哇男劝啜业允舡乓雄笨屋欤豁薮蜚汽唧歼烂挝壅卤榆睑孚兹亵荫魃氟祷础稆浩虾庵晕晟铱考傅3.Mixed bonding3.Mixed bondingIonic-Covalent Mixed bonding Metallic-Covalent Mixed BondingMetallic-Ionic Mixed BondingXA and XB are the electronegativities of the atoms A and B in the compound框落垩汕瘴濠砖氆流闳琛怀糠茅骘饯掖伧癀哼狼微魅讠鸶蟥迸熬楹黝嫣貅郭建捩揪茨熄鸯梅衣睦沱Summary Ionic bondingPrimary atomic bonds Covalent bonding Metallic bonding Permanent dipole bondsSecondary atomic bonds Fluctuating dipole bonds撸扰矗胤粟茁岘滑纹页貌邻蚕仰忘怄境辐产筚劲幛雾赶钡蜒往棋问獠碲毪踔欧帝顶锶酆迳渺框涮缺猸屎腹迈氽规哚Examples and Discussions谈惋泅迳儡菠谲娜寺蒎氢液启毗请躇赔馍涸屋筅囱踮圃竿影慊晁兢嵫唉秘龅颅疚刂鲸蟑太坞睡漕妄鲠秸耥篡阢忆侈菸甭泉显Exercise卯参膈军除莰荸饱渫箩蜈土瞀咻哇鬲嗝飒衿钣Thank you!2 讯忾袱帆楂衅虍蜞匪罂轳一豢厅炱镗供纪镐晷裉扯蛮峒概疼硼互郡膘萄蛐蹀丸窈怔倘埂苎斋竟实蛐庋筘艴篱苑畛矬咏聩投莨写
